This file was created by the Typo3 extension sevenpack version 0.7.14 --- Timezone: CEST Creation date: 2013-05-26 Creation time: 08-27-54 --- Number of references 228 inproceedings ChuangNB2013 2013 7 1-10 Here, a descriptive study is reported that addresses the relationship between flight control performance and instrument scanning behavior. This work was performed in a fixed-based flight simulator. It targets the ability of untrained novices to pilot a lightweight rotorcraft in a flight scenario that consisted of fundamental mission task elements such as speed and altitude changes. The results indicate that better control performance occurs when gaze is more selective for and focused on key instruments. Ideal instrument scanning behavior is proposed and its relevance for training instructions and visual instrument design is discussed. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2013/HCI-I-2013-Chuang.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.hcii2013.org/ Las Vegas, NV, USA 15th International Conference on Human-Computer Interaction (HCI International 2013) accepted chuangLLChuang fmnieuwenhuizenFMNieuwenhuizen hhbHHBülftoff article BonevCE2012 Pattern Recognition Letters 2013 5 34 7 723–730 In this paper we propose an information-theoretic approach to understand eye-movement patterns, in relation to the task performed and image complexity. We commence with the analysis of the distributions and amplitudes of eye-movement saccades, performed across two different image-viewing tasks: free viewing and visual search. Our working hypothesis is that the complexity of image information and task demands should interact. This should be reflected in the Markovian pattern of short and long saccades. We compute high-order Markovian models of performing a large saccade after many short ones and also propose a novel method for quantifying image complexity. The analysis of the interaction between high-order Markovianity, task and image complexity supports our hypothesis. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sciencedirect.com/science/article/pii/S0167865512001687 10.1016/j.patrec.2012.05.007 BBonev chuangLLChuang FEscolano article SchultzBBP2012 Cerebral Cortex 2013 5 23 5 1167-1178 Facial motion carries essential information about other people's emotions and intentions. Most previous studies have suggested that facial motion is mainly processed in the superior temporal sulcus (STS), but several recent studies have also shown involvement of ventral temporal face-sensitive regions. Up to now, it is not known whether the increased response to facial motion is due to an increased amount of static information in the stimulus, to the deformation of the face over time, or to increased attentional demands. We presented nonrigidly moving faces and control stimuli to participants performing a demanding task unrelated to the face stimuli. We manipulated the amount of static information by using movies with different frame rates. The fluidity of the motion was manipulated by presenting movies with frames either in the order in which they were recorded or in scrambled order. Results confirm higher activation for moving compared with static faces in STS and under certain conditions in ventral temporal face-sensitive regions. Activation was maximal at a frame rate of 12.5 Hz and smaller for scrambled movies. These results indicate that both the amount of static information and the fluid facial motion per se are important factors for the processing of dynamic faces. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/Cerebral-Cortex-2012-Schultz.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://cercor.oxfordjournals.org/content/23/5/1167.full.pdf+html 10.1093/cercor/bhs106 johannesJSchultz mabrockhausMBrockhaus hhbHHBülthoff kpilzKPilz article SonFLKBR2012 IEEE Transactions on Cybernetics 2013 4 43 2 597-609 In this paper, we investigate the effect of haptic cueing on a human operator's performance in the field of bilateral teleoperation of multiple mobile robots, particularly multiple unmanned aerial vehicles (UAVs). Two aspects of human performance are deemed important in this area, namely, the maneuverability of mobile robots and the perceptual sensitivity of the remote environment. We introduce metrics that allow us to address these aspects in two psychophysical studies, which are reported here. Three fundamental haptic cue types were evaluated. The Force cue conveys information on the proximity of the commanded trajectory to obstacles in the remote environment. The Velocity cue represents the mismatch between the commanded and actual velocities of the UAVs and can implicitly provide a rich amount of information regarding the actual behavior of the UAVs. Finally, the Velocity+Force cue is a linear combination of the two. Our experimental results show that, while maneuverability is best supported by the Force cue feedback, perceptual sensitivity is best served by the Velocity cue feedback. In addition, we show that large gains in the haptic feedbacks do not always guarantee an enhancement in the teleoperator's performance. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/2013a-SonFraChuKimBueRob.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6294459 10.1109/TSMCB.2012.2212884 chakurtHISon antonioAFranchi chuangLLChuang junsukkimJKim hhbHHBülthoff robu_paPRobuffo Giordano article WallravenD2013 NeuroReport 2013 3 24 5 254–258 Humans are experts for face processing - this expertise develops over the course of several years, given visual input about faces from infancy. Recent studies have shown that individuals can also recognize faces haptically, albeit at lower performance than visually. Given that blind individuals are extensively trained on haptic processing, one may expect them to perform better at recognizing faces from touch than sighted individuals. Here, we tested this hypothesis using matched groups of sighted, congenitally blind, and acquired-blind individuals. Surprisingly, we found little evidence for a performance benefit for blind participants compared with sighted controls. Moreover, the congenitally blind group performed significantly worse than both the sighted and the acquired-blind group. Our results are consistent with the hypothesis that visual expertise may be necessary for haptic face recognition; hence, even extensive haptic training cannot easily account for deficits in visual processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff 10.1097/WNR.0b013e32835f00c0 walliCWallraven ldopjansLDopjans conference Chuang2012 2012 11 2 We pick out task-relevant information from the visual scene by moving our eyes and confidently manipulate our near-environment to achieve our goals. A better understanding of human behavior can be achieved by adopting this perspective. That is, humans are active (not passive observers). In my talk, I will address how we characterize natural information-seeking behavior in human participants in two context: a) scene processing, b) object learning. The first addresses how unrestrained gaze behavior can be characterized in terms of the information that is available in the scene. Here, I will explain why and how we eschew pure bottom-up procedures of using low-level image statistics to predict gaze movements. Next, I will discuss how we select which views of unfamiliar objects to learn, when we are free to manipulate them in 3D. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Invited Lecture Singapore Department of Cognitive Neuroscience: Duke-NUS Graduate Medical School chuangLChuang poster EsinsSKWB2012_2 2012 11 13 38 Congenital prosopagnosia, an innate impairment in recognizing faces, as well as the otherrace-effect, the disadvantage in recognizing faces of foreign races, both influence face recognition abilities. Here we compared both phenomena by testing three groups: German congenital prosopagnosics (cPs), unimpaired German and unimpaired South Korean participants (n=23 per group), on three tests with Caucasian faces. First we ran the Cambridge Face Memory Test (Duchaine & Nakayama, 2006 Neuropsychologia 44 576-585). Participants had to recognize Caucasian target faces in a 3AFC task. German controls performed better than Koreans (p=0.009) who performed better than prosopagnosics (p=0.0001). Variation of the individual performances was larger for cPs than for Koreans (p = 0.028). In the second experiment, participants rated the similarity of Caucasian faces (in-house 3D face-database) which differed parametrically in features or second order relations (configuration). We found differences between sensitivities to change type (featural or configural, p=0) and between groups (p=0.005) and an interaction between both factors (p = 0.019). During the third experiment, participants had to learn exemplars of artificial objects (greebles), natural objects (shells), and faces and recognize them among distractors. The results showed an interaction (p = 0.005) between stimulus type and participant group: cPs where better for non-face stimuli and worse for face stimuli than the other groups. Our results suggest that congenital prosopagnosia and the other-race-effect affect face perception in different ways. The broad range in performance for the cPs directs the focus of our future research towards looking for different forms of congenital prosopagnosia. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.neuroschool-tuebingen-nena.de/ Schramberg, Germany 13th Conference of the Junior Neuroscientists of Tübingen (NeNA 2012) esinsJEsins johannesJSchultz BRKim walliCWallraven isaIBülthoff conference NieuwenhuizenCB2012 2012 11 The volume of both road and air transportation continues to increase despite many concerns regarding its financial and environmental impact. The European Union ‘Out of the Box’ study suggests a personal aerial transportation system (PATS) as an alternative means of transport for daily commuting. The aim of the myCopter project is to determine the social and technical aspects needed to set up such a transportation system based on personal aerial vehicles (PAVs). The project focuses on three research areas: the human-machine interface and training, automation technologies, and social acceptance. In the first phase of the project, requirements were defined for automation technologies in terms of sensors and test platforms. Additionally, desirable features for PAVs were investigated to support the design and evaluation of technologies for an effective human-machine interface. Furthermore, an overview of the social-technological environment provided insight into the challenges and issues that surround the realisation of a PATS and its integration into the current transportation system in Europe. The presentation will elaborate on the second phase of the myCopter project, in which initial designs for a human-machine interface and training are developed. These are evaluated experimentally with a focus on aiding non-expert pilots in closed-loop control scenarios. Additionally, first evaluations of novel automation technologies are performed in simulated environments and evaluations on flying test platforms. At the same time, technological issues are evaluated that contribute towards a reflexive design of PAV technologies based on criteria that are acceptable to the general public. The presentation will also focus on the next stages of the project, in which further experimental evaluations will be performed on technologies for human-machine interfaces, and where developed automation technologies will be fully tested on unmanned flying vehicles. The expectations and perspectives of potential PAV user will be evaluated in group interviews in different European countries. Interesting technological and regulatory challenges need to be resolved for the development of a transportation system based on PAVs. The myCopter consortium combines the expertise from several research fields to tackle these challenges and to develop the technological and social aspects of a personal aerial transportation system. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/HELIWorld-2012-Nieuwenhuizen.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk Frankfurt a.M., Germany 4th International HELI World Conference at the International Aerospace Supply Fair AIRTEC 2012 fmnieuwenhuizenFNieuwenhuizen chuangLChuang hhbHHBülthoff article BiegBBC2012 PLoS ONE 2012 9 7 9 1-9 Recent studies provide evidence for task-specific influences on saccadic eye movements. For instance, saccades exhibit higher peak velocity when the task requires coordinating eye and hand movements. The current study shows that the need to process task-relevant visual information at the saccade endpoint can be, in itself, sufficient to cause such effects. In this study, participants performed a visual discrimination task which required a saccade for successful completion. We compared the characteristics of these task-related saccades to those of classical target-elicited saccades, which required participants to fixate a visual target without performing a discrimination task. The results show that task-related saccades are faster and initiated earlier than target-elicited saccades. Differences between both saccade types are also noted in their saccade reaction time distributions and their main sequences, i.e., the relationship between saccade velocity, duration, and amplitude. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.plosone.org/article/fetchObjectAttachment.action;jsessionid=409E420397B230BE376365245B458D2A?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0045445&representation=PDF 10.1371/journal.pone.0045445 e45445 biegH-JBieg brescianiJ-PBresciani hhbHHBülthoff chuangLLChuang poster BiegBBC2012_2 Perception 2012 9 41 ECVP Abstract Supplement 137 Smooth pursuit eye movements can be interrupted and resumed at a later stage, eg, when a concurrent task requires visual sampling from elsewhere. Here we address whether and how interruptive saccades are affected by pursuit movements. Our participants pursued an object which moved horizontally in a sinusoidal pattern (frequency: 0.25 Hz, amplitude: 4 deg. visual angle). During this, discrimination targets appeared at 10 deg. eccentricity, to the left or right of the center. They were timed so that they appeared for 1 second while the pursuit object moved either toward or away from the discrimination target's position. Saccade reaction times were earlier when the discrimination targets appeared in a position that the tracking object was moving towards. Interestingly, saccade RTs back to the pursuit object were shorter when the object moved away from the discrimination target. We conclude that interruptions of pursuit movements lead to asymmetries in saccade generation. These asymmetries could have been caused by biases in attention along the predicted pursuit path. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v120443 Alghero, Italy 35th European Conference on Visual Perception biegH-JBieg brescianiJ-PBresciani hhbHHBülthoff chuangLLChuang poster EsinsBKS2012 Perception 2012 9 41 ECVP Abstract Supplement 113 Congenital prosopagnosia, the innate impairment in recognizing faces exhibits diverse deficits. Due to this heterogeneity the possible existence of subgroups of the impairment was suggested (eg Kress and Daum, 2003 Behavioural Neurology14109-21). We examined 23 congenital prosopagnosics (cPAs) identified via a screening questionnaire (as used in Stollhoff, Jost, Elze, and Kennerknecht, 2011 PLoS ONE6e15702) and 23 age-, gender and educationally matched controls with a battery consisting of nine different tests. These included well known tests like the Cambridge Face Memory Test (CFMT, Duchaine and Nakayama, 2006 Neuropsychologia44576-85), a Famous Face Test (FFT), and new, own tests about object and face recognition. As expected, cPAs had lower CFMT and FFT scores than the controls. Analyses of the performance patterns across the nine tests suggest the existence of subgroups within both cPAs and controls. These groups could not be revealed only based on the CFMT and FFT scores, indicating the necessity of tests addressing different, specific aspects of object and face perception for the identification of subgroups. Current work focuses on characterizing the subgroups and identifying the most useful tests. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v120524 Alghero, Italy 35th European Conference on Visual Perception esinsJEsins isaIBülthoff IKennerknecht johannesJSchultz poster ChuangNB2012 Perception 2012 9 41 ECVP Abstract Supplement 99 How are eye-movements planned to access relevant visual information during flight control? From the cockpit perspective, there are two classes of visual information that are relevant for flight control. First, the changing visuals of the external world provide direct perceptual feedback on how the pilot's command of the control stick is affecting the aircraft's current position, orientation and velocity. Second, flight instruments provide abstracted and specific values—on factors such as the aircraft's compass bearing and vertical speed—that have to be continuously monitored, in order for the global objective of certain maneuvers (eg, turns) to be achieved. Trained pilots have to coordinate their eye-movements across this structured visual workspace (ie, outside view and instruments) to access timely and task-relevant information. The current work focuses on providing descriptions of these planned eye-movements. Eye-movements were recorded of pilots in a high-fidelity flight simulator (100° field-of-view) whilst they performed specific flight maneuvers. Fixation durations and transitions between the individual instruments and aspects of the external environment are represented as network graphs. This allowed us to formally describe the sources of information that were relied on across the different tasks and to compare actual performance to expert predictions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v120634 Alghero, Italy 35th European Conference on Visual Perception chuangLChuang fmnieuwenhuizenFNieuwenhuizen hhbHHBülthoff poster KaulardSWBd2012 Perception 2012 9 41 ECVP Abstract Supplement 103 The face inversion effect has often been demonstrated in face identification tasks. Less is known about whether processes underlying face expression recognition are also sensitive to face inversion. Face expression recognition is usually investigated using pictures of six emotional expressions. In everyday life, humans are however exposed to a much larger set of facial expressions, which are dynamic. Here, we examine the effect of face inversion on expression recognition for a variety of facial expressions displayed statically and dynamically. We measured participants'recognition accuracy for 12 expressions using a 13 alternative-forced-choice task. We varied the dynamics (videos versus pictures) and the orientation (upright versus inverted) of the presentation of the expressions in a completely crossed design. Accuracy was significantly higher when expressions were presented as videos (62%) than as pictures (47%). Similarly, recognition accuracy was significantly higher for upright (84%) compared to inverted (64%) expressions. Moreover, the effect of orientation changed significantly with expression type. No other effects were significant. This is the first study to report that face inversion affects the recognition of natural facial expressions. Because face inversion effects are interpreted as a sign of configural processing, our results suggest configural processing for a majority of facial expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v120193 Alghero, Italy 35th European Conference on Visual Perception kascotKKaulard johannesJSchultz walliCWallraven hhbHHBülthoff delarosaSde la Rosa poster ChuangNB2012_2 2012 9 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://research.fit.edu/hci-aero/hci-aero2012/Poster_Sessions.html Bruxelles, Belgium International Conference on Human-Computer Interaction in Aerospace (HCI-Aero 2012) chuangLLChuang fmnieuwenhuizenFMNieuwenhuizen hhbHHBülthoff conference SchultzFdBK2012 Perception 2012 9 41 ECVP Abstract Supplement 38 The dynamic facial expressions that we encounter every day can carry a myriad of social signals. What are the neural mechanisms allowing us to decode these signals? A useful basis for this decoding could be representations in which the facial expressions are set in relation to each other. Here, we compared the behavioral and neural representations of 12 facial expressions presented as pictures and videos. Behavioral representations of these expressions were computed based on the results of a semantic differential task. Neural representations of these expressions were obtained by multivariate pattern analysis of functional magnetic imaging data. The two kinds of representations were compared using correlations. For expression videos, the results show a significant correlation between the behavioral and neural representations in the superior temporal sulcus (STS), the fusiform face area, the occipital face area and the amygdala, all in the left hemisphere. For expression pictures, a significant correlation was found only in the left STS. These results suggest that of all tested regions, the left STS contains the neural representation of facial expressions that is closest to their behavioral representation. This confirms the predominant role of STS in coding changeable aspects of faces, which includes expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v120194 Alghero, Italy 35th European Conference on Visual Perception johannesJSchultz anaferALFernandez Cruz delarosaSde la Rosa hhbHHBülthoff kascotKKaulard article GaissertWFB2012 PLoS One 2012 8 7 8 1-7 Categorization and categorical perception have been extensively studied, mainly in vision and audition. In the haptic domain, our ability to categorize objects has also been demonstrated in earlier studies. Here we show for the first time that categorical perception also occurs in haptic shape perception. We generated a continuum of complex shapes by morphing between two volumetric objects. Using similarity ratings and multidimensional scaling we ensured that participants could haptically discriminate all objects equally. Next, we performed classification and discrimination tasks. After a short training with the two shape categories, both tasks revealed categorical perception effects. Training leads to between-category expansion resulting in higher discriminability of physical differences between pairs of stimuli straddling the category boundary. Thus, even brief training can alter haptic representations of shape. This suggests that the weights attached to various haptic shape features can be changed dynamically in response to top-down information about class membership. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0043062 10.1371/journal.pone.0043062 e43062 ninagaissertNGaissert swaterkaSWaterkamp rolandRWFleming isaIBülthoff inproceedings BiegCFRB2012 2012 8 341-344 In der vorliegenden Studie wurde der Einfluss visueller Ablenkung auf Steuerungsaufgaben untersucht. Die Ergebnisse deuten darauf hin, dass bereits eine kurze Verlagerung der Aufmerksamkeit und des Blicks mit einer systematischen Beeinflussung der Steuerungsaufgabe einhergeht. Im Gegenzug findet auch eine systematische Beeinflussung der Augenbewegungen durch die gleichzeitig durchgeführte Steuerungsaufgabe statt. Die Berücksichtigung solcher Interferenzen kann bei der Entwicklung von grafischen On-Board-Informationssystemen für Fahr- oder Flugzeuge von Nutzen sein. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://dl.mensch-und-computer.de/handle/123456789/2907 Reiterer, H. , O. Deussen Oldenbourg

München, Germany

Mensch & Computer 2012: 12. fachübergreifende Konferenz für interaktive und kooperative Medien Konstanz, Germany Mensch & Computer (M&C) 978-3-486-71879-9 biegH-JBieg hhbHHBülthoff chuangLLChuang poster DobsBCS2012 Journal of Vision 2012 8 12 9 35 Previous research has shown that facial motion can convey information about identity in addition to facial form (e.g. Hill & Johnston, 2001). The present study aims at finding whether identity judgments vary depending on the kinds of facial movements and the task performed. To this end, we used a recent facial motion capture and animation system (Curio et al., 2006). We recorded different actors performing classic emotional facial movements (e.g. happy, sad) and non-emotional facial movements occurring in social interactions (e.g. greetings, farewell). Only non-rigid components of these facial movements were used to animate one single avatar head. In a between-subject design, four groups of participants performed identity judgments based on emotional or social facial movements in a same-different (SD) or a delayed matching-to-sample task (XAB). In the SD task, participants watched two distinct facial movements (e.g. happy and sad) and had to choose whether the same or different actors performed these facial movements. In the XAB task, participants saw one target facial movement X (e.g. happy) performed by one actor followed by two facial movements of another kind (e.g. sad) performed by two actors. Participants chose which of the latter facial movements was performed by the same actor as the one performing X. Prior to the experiment, participants were familiarized with the actors by watching them perform facial movements not subsequently tested. Participants were able to judge actor identities correctly in all conditions, except for the SD task performed on the emotional stimuli. Sensitivity to identity as measured by d-prime was higher in the XAB than in the SD task. Furthermore, performance was higher for social than for emotional stimuli. Our findings reveal an effect of task on identity judgments based on facial motion, and suggest that such judgments are easier when facial movements are less stereotypical. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/12/9/35.abstract Max Planck Institue for Biological Cybernetics Naples, FL, USA 12th Annual Meeting of the Vision Sciences Society (VSS 2012) kdobsKDobs isaIBülthoff curioCCurio johannesJSchultz poster Bulthoff2012_5 Journal of Vision 2012 8 12 9 1282 We can quickly and easily judge faces in terms of their ethnicity. What is the basis for our decision? Other studies have used either eye tracking (e.g., Armann & Bülthoff 2009) or the Bubbles method (e.g., Gosselin & Schyns 2001) in categorization tasks to investigate which facial features are used for sex or identity classification. The first method investigates which parts are preferentially looked at while the latter method shows which facial regions, when shown in isolation during the task, leads to correct classification. Here we measured the influence of facial features on ethnicity classification when they are embedded in the face of the other ethnicity. Asian and Caucasian faces of our 3D face database (http://faces.kyb.tuebingen.mpg.de) had been paired according to sex, age and appearance. We used 18 pairs of those Asian-Caucasian faces to create a variety of mixed-race faces. Mixed-race faces were obtained by exchanging one of the following facial features between both faces of a pair: mouth, nose, facial contour, shape, texture (skin) and eyes. We showed original and modified faces one by one in a simple ethnicity classification task. All faces were turned 20 degrees to the side for a more informative view of nose shape, face shape and facial contour while eyes and mouth and general face textures were still fully visible. Because of skin color differences between exchanged parts and original faces, all 3D faces were rendered as grey-level images. The results of 24 Caucasian participants show that the eyes and the texture of a face are major determinants for ethnicity classification, more than face shape and face contour, while mouth and nose had weak influence. Response times showed that participants were faster at classifying less ambiguous faces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/12/9/1282.abstract Naples, FL, USA 12th Annual Meeting of the Vision Sciences Society (VSS 2012) isaIBülthoff conference KimESBW2012 2012 7 15 8 65 The fact that people are better at recognizing faces of their own race than others is called the other-race-effect (ORE). Most studies use only a single test to map and determine the characteristics of the ORE, however. Here, we investigated how two groups of fifteen age-matched Korean and German participants recognize Asian and Caucasian faces with three experiments as part of testing a new battery for characterizing face-processing performance. Participants first underwent the standard Cambridge face memory test in which they had to learn Caucasian target faces at varying noise levels which then were to be recognized in a forced-choice task. In this task, German participants performed significantly better than Koreans (83% versus 72%). The second experiment used a standard old-new recognition task with 20 Caucasian and 20 Asian faces (courtesy of the tarrlab@CMU). Here, Koreans were better with Asian faces (d’-difference=1.23) whereas Germans only showed a tendency towards an ORE (d’-difference=0.44). In the third experiment, participants had to rate the similarity of Caucasian face pairs which varied parametrically along featural and configural dimensions using the morphable faces from the MPI face-database. Here, we found that Korean participants were significantly less sensitive to featural changes than German participants. In conclusion, we were able to demonstrate an ORE for most of our experimental conditions. Interestingly, data from the third experiment suggests that the ORE may be due more to lessened sensitivity to featural than to configural processing for other-race faces. Future studies will extend this new test battery to prosopagnosics. Acknowledgement: This research was supported by the World Class University (WCU) program through the National Research Foundation of Korea funded by the Ministry of Education, Science, and Technology (R31-1008-000-10008-0). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://apcv2012.com/ Incheon, South Korea 8th Asia-Pacific Conference on Vision (APCV 2012) BRKim esinsJEsins johannesJSchultz isaIBülthoff walliCWallraven poster EsinsSKWB2012 2012 7 8 57 Congenital prosopagnosia, an innate impairment in recognizing faces, as well as the other-race-effect, the disadvantage in recognizing faces of foreign races, both influence face recognition abilities. Here we compared both phenomena by testing three groups: German congenital prosopagnosics (cPs), unimpaired German and unimpaired South Korean participants (n=23 per group), on three tests with Caucasian faces. First we ran the Cambridge Face Memory Test (Duchaine & Nakayama, 2006 Neuropsychologia 44 576-585). Participants had to recognize Caucasian target faces in a 3AFC task. German controls performed better than Koreans (p=0.009) who performed better than prosopagnosics (p=0.0001). Variation of the individual performances was larger for cPs than for Koreans (p = 0.028). In the second experiment, participants rated the similarity of Caucasian faces (in-house 3D face-database) which differed parametrically in features or second order relations (configuration). We found differences between sensitivities to change type (featural or configural, p=0) and between groups (p=0.005) and an interaction between both factors (p = 0.019). During the third experiment, participants had to learn exemplars of artificial objects (greebles), natural objects (shells), and faces and recognize them among distractors. The results showed an interaction (p = 0.005) between stimulus type and participant group: cPs where better for non-face stimuli and worse for face stimuli than the other groups. Our results suggest that congenital prosopagnosia and the other-race-effect affect face perception in different ways. The broad range in performance for the cPs directs the focus of our future research towards looking for different forms of congenital prosopagnosia. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/APCV-2012-Poster-Esins.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://apcv2012.com/ Incheon, South Korea 8th Asia-Pacific Conference on Vision (APCV 2012) esinsJEsins johannesJSchultz BRKim walliCWallraven isaIBülthoff poster JungAB2012 2012 7 8 60 What gives a face its race?By biological criteria, human “races” do not exist (e.g., Cosmides et al., 2003). Nevertheless, every-day life and research from various fields show that we robustly and reliably perceive humans as belonging to different race groups. Here, we investigate the bases for our quick and easy judgments, by measuring the influence of manipulated facial features on race classification. Asian and Caucasian faces of our 3-dimensional face database (http://faces.kyb.tuebingen.mpg.de) were paired according to sex, age and overall appearance. With these Asian-Caucasian face pairs we created a variety of mixed-race faces, by exchanging facial features between both faces of a pair: eyes, nose, mouth, “outer” features, shape or texture. Original and modified faces were shown in a simple race classification task. We tested 24 Westerners (Germany) and 24 Easterners (South Korea). In both groups, eyes and texture were major determinants for race classification, followed by face shape, and then outer features, mouth, nose, which only had a weak influence on perceived face. Eastern participants classified Caucasian original faces better than Asian original faces, while Western participants were similarly good at classifying both races. Western participants - but not their Eastern counterparts - were less susceptible to eye, shape and texture manipulations in other-race faces than in their own-race faces. A closer look at the data suggests that this effect mainly originates from differences in processing male and female faces in Western participants only. Our results provide more evidence of differences between observers from different cultural and ethnic backgrounds in face perception and processing. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/APCV-2012-Jung.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://apcv2012.com/ Incheon, South Korea 8th Asia-Pacific Conference on Vision (APCV 2012) WJung armannRArmann isaIBülthoff article ArmannB2011 Vision Research 2012 6 63 69–80 Categorical perception (CP) is a fundamental cognitive process that enables us to sort similar objects in the world into meaningful categories with clear boundaries between them. CP has been found for high-level stimuli like human faces, more precisely, for the perception of face identity, expression and ethnicity. For sex however, which represents another important and biologically relevant dimension of human faces, results have been equivocal so far. Here, we reinvestigate CP for sex using newly created face stimuli to control two factors that to our opinion might have influenced the results in earlier studies. Our new stimuli are (a) derived from single face identities, so that changes of sex are not confounded with changes of identity information, and (b) “normalized” in their degree of maleness and femaleness, to counteract natural variations of perceived masculinity and femininity of faces that might obstruct evidence of categorical perception. Despite careful normalization, we did not find evidence of CP for sex using classical test procedures, unless participants were specifically familiarized with the face identities before testing. These results support the single-route hypothesis, stating that sex and identity information in faces are not processed in parallel, in contrast to what was suggested in the classical Bruce and Young model of face perception. Besides, interestingly, our participants show a consistent bias, before and after perceptual normalization of the male–female range of the test morph continua, to judge faces as male rather than female. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sciencedirect.com/science/article/pii/S0042698912001496 10.1016/j.visres.2012.05.005 armannRArmann isaIBülthoff article ChuangVB2012_2 Frontiers in Computational Neuroscience 2012 5 6 26 1-8 There is evidence that observers use learned object motion to recognize objects. For instance, studies have shown that reversing the learned direction in which a rigid object rotated in depth impaired recognition accuracy. This motion reversal can be achieved by playing animation sequences of moving objects in reverse frame order. In the current study, we used this sequence-reversal manipulation to investigate whether observers encode the motion of dynamic objects in visual memory, and whether such dynamic representations are encoded in a way that is dependent on the viewing conditions. Participants first learned dynamic novel objects, presented as animation sequences. Following learning, they were then tested on their ability to recognize these learned objects when their animation sequence was shown in the same sequence order as during learning or in the reverse sequence order. In Experiment 1, we found that non-rigid motion contributed to recognition performance; that is, sequence-reversal decreased sensitivity across different tasks. In subsequent experiments, we tested the recognition of non-rigidly deforming (Experiment 2) and rigidly rotating (Experiment 3) objects across novel viewpoints. Recognition performance was affected by viewpoint changes for both experiments. Learned non-rigid motion continued to contribute to recognition performance and this benefit was the same across all viewpoint changes. By comparison, learned rigid motion did not contribute to recognition performance. These results suggest that non-rigid motion provides a source of information for recognizing dynamic objects, which is not affected by changes to viewpoint. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.frontiersin.org/Journal/DownloadFile.ashx?pdf=1&FileId=%2062343&articleId=%2022441&Version=%201&ContentTypeId=21&FileName=%20fncom-06-00026.pdf 10.3389/fncom.2012.00026 chuangLLChuang qvuongQCVuong hhbHHBülthoff poster PerdikisMKWL2012 2012 5 Humans recognize facial emotional expressions (FEEs) better when FEEs are presented dynamically than through static images. Wallraven et al. 2008 propose that humans are sensitive to the natural dynamics of FEEs. Moreover, PET/fMRI studies suggest that differentiated brain networks process static and dynamic FEEs. However, in most cases, dynamic FEEs have been created out of static ones, using linear morphing techniques. Together with the low time resolution of PET/fMRI, such studies fail to capture the modulation of the activated brain networks by the subtle (and highly nonlinear) dynamics of FEEs. Our ongoing study investigates EEG responses to static and dynamic FEEs drawn from an ecologically valid database (Kaulard et al. 2008, Kaulard et al. 2009). “Happy” and “angry” FEEs performed by two male and two female actors are displayed to twenty female participants in an “oddball” experimental paradigm. Blocks of either dynamic or static stimuli that differ in their emotional content (“happy” versus “angry” and reverse) are presented in a pseudorandom order. The task consists of pressing a keyboard button upon appearance of a deviant stimulus. Data analysis focuses on synchrony and nonlinear coupling of sensor as well as source dynamics (as a bridge to PET/fMRI studies), both in the time-frequency and in the phase-space domain, to identify the brain networks that emerge and evolve dynamically in each condition. Preliminary results from pilot data analysis confirm the PET/fMRI findings of enhanced and differentiated brain activations for dynamic FEEs compared to static ones. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://escan2012.sciencesconf.org/4021 Marseille, France 1st Conference of the European Society for Cognitive and Affective Neuroscience (ESCAN 2012) DPerdikis VMüller kascotKKaulard walliCWallraven ULindenberg article HelbigERPTMSN2011 NeuroImage 2012 4 60 2 1063–1072 Behaviourally, humans have been shown to integrate multisensory information in a statistically-optimal fashion by averaging the individual unisensory estimates according to their relative reliabilities. This form of integration is optimal in that it yields the most reliable (i.e. least variable) multisensory percept. The present study investigates the neural mechanisms underlying integration of visual and tactile shape information at the macroscopic scale of the regional BOLD response. Observers discriminated the shapes of ellipses that were presented bimodally (visual-tactile) or visually alone. A 2×5 factorial design manipulated (i) the presence vs. absence of tactile shape information and (ii) the reliability of the visual shape information (five levels). We then investigated whether regional activations underlying tactile shape discrimination depended on the reliability of visual shape. Indeed, in primary somatosensory cortices (bilateral BA2) and the superior parietal lobe the responses to tactile shape input were increased when the reliability of visual shape information was reduced. Conversely, tactile inputs suppressed visual activations in the right posterior fusiform, when the visual signal was blurred and unreliable. Somatosensory and visual cortices may sustain integration of visual and tactile shape information either via direct connections from visual areas or top-down effects from higher order parietal areas. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Research Group Ernst Department Scheffler Department Schölkopf Research Group Noppeney http://www.sciencedirect.com/science/article/pii/S1053811911011475 10.1016/j.neuroimage.2011.09.072 helbigHBHelbig marcMOErnst ricciardiERicciardi PPietrini thielscherAThielscher kamaKMMayer johannesJSchultz unoppeUNoppeney article KaulardCBW2012 PLoS One 2012 3 7 3 1-18 The ability to communicate is one of the core aspects of human life. For this, we use not only verbal but also nonverbal signals of remarkable complexity. Among the latter, facial expressions belong to the most important information channels. Despite the large variety of facial expressions we use in daily life, research on facial expressions has so far mostly focused on the emotional aspect. Consequently, most databases of facial expressions available to the research community also include only emotional expressions, neglecting the largely unexplored aspect of conversational expressions. To fill this gap, we present the MPI facial expression database, which contains a large variety of natural emotional and conversational expressions. The database contains 55 different facial expressions performed by 19 German participants. Expressions were elicited with the help of a method-acting protocol, which guarantees both well-defined and natural facial expressions. The method-acting protocol was based on every-day scenarios, which are used to define the necessary context information for each expression. All facial expressions are available in three repetitions, in two intensities, as well as from three different camera angles. A detailed frame annotation is provided, from which a dynamic and a static version of the database have been created. In addition to describing the database in detail, we also present the results of an experiment with two conditions that serve to validate the context scenarios as well as the naturalness and recognizability of the video sequences. Our results provide clear evidence that conversational expressions can be recognized surprisingly well from visual information alone. The MPI facial expression database will enable researchers from different research fields (including the perceptual and cognitive sciences, but also affective computing, as well as computer vision) to investigate the processing of a wider range of natural facial expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032321 10.1371/journal.pone.0032321 e32321 kascotKKaulard dwcDWCunningham hhbHHBülthoff walliCWallraven article GaissertW2011_2 Experimental Brain Research 2012 1 216 1 123-134 Although the hands are the most important tool for humans to manipulate objects, only little is known about haptic processing of natural objects. Here, we selected a unique set of natural objects, namely seashells, which vary along a variety of object features, while others are shared across all stimuli. To correctly interact with objects, they have to be identified or categorized. For both processes, measuring similarities between objects is crucial. Our goal is to better understand the haptic similarity percept by comparing it to the visual similarity percept. First, direct similarity measures were analyzed using multidimensional scaling techniques to visualize the perceptual spaces of both modalities. We find that the visual and the haptic modality form almost identical perceptual spaces. Next, we performed three different categorization tasks. All tasks exhibit a highly accurate processing of complex shapes of the haptic modality. Moreover, we find that objects grouped into the same category form regions within the perceptual space. Hence, in both modalities, perceived similarity constitutes the basis for categorizing objects. Moreover, both modalities focus on shape to form categories. Taken together, our results lead to the assumption that the same cognitive processes link haptic and visual similarity perception and the resulting categorization behavior. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.springerlink.com/content/h8174v8813827266/fulltext.pdf 10.1007/s00221-011-2916-4 ninagaissertNGaissert walliCWallraven article DopjansBW2012 Journal of Vision 2012 1 12 1:6 1-14 Even though we can recognize faces by touch surprisingly well, haptic face recognition performance is still worse than for visual exploration. One possibility for this performance difference might be due to different encoding strategies in the two modalities, namely, holistic encoding in vision versus serial encoding in haptics. Here, we tested this hypothesis by promoting serial encoding in vision, using a novel, gaze-restricted display that limited the effective field of view in vision to resemble that of haptic exploration. First, we compared haptic with gaze-restricted and unrestricted visual face recognition. Second, we used the face inversion paradigm to assess how encoding differences might affect processing strategies (featural vs. holistic). By promoting serial encoding in vision, we found equal face recognition performance in vision and haptics with a clear switch from holistic to featural processing, suggesting that performance differences in visual and haptic face recognition are due to modality-specific encoding strategies. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/12/1/6.full.pdf+html 10.1167/12.1.6 ldopjansLDopjans hhbHHBülthoff walliCWallraven conference Chuang2011_4 2011 11 2 As active observers, we move our eyes, re-orient our bodies and even manipulate our environment to access task-relevant information. The purpose of this talk is demonstrate that our understanding of human behavior can be enriched by considering that the observer is often-times responsible for his own perceptual input. I will do so by first presenting research that: a) addressed how object speeds are estimated during locomotion, b) investigated how we explore objects during learning for subsequent recognition. Following this, I will present research in two application scenarios that exemplifies the role of the active observer — namely, teleoperation of swarm-UAVs and gazetracking on wall-sized displays. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Invited Lecture http://ikw.uni-osnabrueck.de/en/node/680 Max Planck Institute for Biological Cybernetics Osnabrück, Germany Institute of Cognitive Science, Universität Osnabrück chuangLChuang article ArmannJCR2011 Journal of Vision 2011 11 11 13:9 1-14 Models of face perception often adopt a framework in which faces are represented as points or vectors in a multidimensional space, relative to the average face that serves as a norm for encoding. Since faces are very similar in their configuration and share many visual properties, they could be encoded in one common space against one norm. However, certain face properties may result in grouping and “subclassification” of similar faces. We studied the processing of faces of different races, using high-level aftereffects, where exposure to one face systematically distorts the perception of a subsequently viewed face toward the “opposite” identity in face space. We measured identity aftereffects for adapt–test pairs that were opposite relative to race-specific (Asian and Caucasian) averages and pairs that were opposite relative to a “generic” average (both races morphed together). Aftereffects were larger for race-specific compared to mixed-race adapt–test pairs. These results suggest that race-specific norms are used to code identity because aftereffects are generally larger for adapt–test pairs drawn from trajectories passing through the norm (opposite pairs) than for those that do not. We also found that identification thresholds were lower when targets were distributed around race-specific averages than around the mixed-race average, suggesting that norm-based face encoding may play a functional role in facilitating identity discrimination. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/11/13/9.full.pdf+html 10.1167/11.13.9 armannRArmann LJeffery AJCalder GRhodes poster PapeWSBM2011 2011 11 41 288.05 Grid cells in entorhinal cortex of freely moving rodents were proposed to provide a universal metric of space. They tile the environment into a six-fold symmetric pattern with a particular orientation relative to the environment. The six-fold rotational symmetry of grid patterns can be used to predict a macroscopic signal to functional magnetic resonance imaging (fMRI) in humans [Doeller et al, 2010, Nature]. During hippocampal remapping, grid pattern orientations in rats also change. The purpose of the present study is to examine whether orientation changes (i.e., remapping) can also be found in humans. Participants learned object locations within a virtual room (see Figure 1 left side) and retrieved locations from different start locations during two scanning sessions. They then navigated into an adjacent room and repeated the procedure. We extracted grid orientations from odd trials, and predicted the BOLD response in even trials as a function of the deviation between running direction and the estimated grid orientation for each session. This prediction was significant for the right entorhinal cortex, replicating earlier findings. In 80% of the cases grid cell orientations significantly differed between sessions both within a room and between rooms (see Figure 1 right side). Switching off the virtual environment between sessions for about one minute was seemingly sufficient for that. For male, but not for female participants, grid cell orientation was clustered around the random view of the room experienced at session start. Data suggests that human grid cell orientations can be rather flexible which might be due to the virtuality of the experience. Grid cell orientation might at least for male participants be related to the initial view of an environment. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sfn.org/am2011/ Washington, DC, USA 41st Annual Meeting of the Society for Neuroscience (Neuroscience 2011) antopiaA-APape TWolbers johannesJSchultz hhbHHBülthoff meilingerTMeilinger inproceedings SonCKB2011 2011 10 1323-1328 The availability of additional force cues in haptic devices are often expected to improve control performance, over conditions that only provide visual feedback. However, there is little empirical evidence to show this to be true for the teleoperation control of remote vehicles (i.e., multiple unmanned aerial vehicles (UAVs)). In this paper, we show that force cues can increase one's sensitivity in discerning the presence of obstacles in the remote multi-UAVs' environment. Significant benefits, relative to a purely visual scenario, were achieved only when force cues were sufficiently amplified by large gains. In addition, force cues tended to provide stronger benefits when they were based on the UAVs' velocity information. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6106130 IEEE

Piscataway, NJ, USA

Gyeonggi-do, Korea 11th International Conference on Control, Automations and Systems (ICCAS 2011) 978-1-4577-0835-0 chakurtHISon chuangLChuang junsukkimJKim hhbHHBülthoff poster LeeBBC2011 2011 10 12 33 How does our visual system decide where to look? The Linear Approach to Threshold with Ergodic Rate (LATER: Carpenter, 1995) is a simple decision-making model for saccadic eye movements. Currently, experimental data suggest that saccadic eye-movements can be discriminated according to whether they are performed for directed fixations or for item recognition (Montagnini & Chelazzi, 2005; Bieg et al., submitted). Unfortunately, sufficient goodness-of-fit can only be acquired with large datasets, for each individual participant. Here, we investigate whether adapting LATER with modern computational methods can allow for saccades to be classified for their functionality, with minimal data and in real-time. In doing so, we strive towards the eventual goal of using the LATER model for predicting observer intentions in real-world applications. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.neuroschool-tuebingen-nena.de/index.php?id=360 Heiligkreuztal, Germany 12th Conference of Junior Neuroscientists of Tübingen (NeNA 2011) jleeJJLee biegH-JBieg hhbHHBülthoff chuangLLChuang poster PapeWSBM2011_2 2011 10 12 38 Grid cells in entorhinal cortex of freely moving rodents were proposed to provide a universal metric of space. They tile the environment into a six-fold symmetric pattern with a particular orientation relative to the environment. The six-fold rotational symmetry of grid patterns can be used to predict a macroscopic signal to functional magnetic resonance imaging (fMRI) in humans [Doeller et al, 2010, Nature]. During hippocampal remapping, grid pattern orientations in rats also change. The purpose of the present study is to examine whether orientation changes (i.e. remapping) can also be found in humans. Participants learned object locations within a virtual room and retrieved locations from different start locations during two scanning sessions. They then navigated into an adjacent room and repeated the procedure. We extracted grid orientations from odd trials, and predicted the BOLD response in even trials as a function of the deviation between running direction and the estimated grid orientation for each session. This prediction was significant for the right entorhinal cortex, replicating earlier findings. In 80% of the cases grid cell orientations significantly differed between sessions both within a room and between rooms. Switching off the virtual environment between sessions for about one minute was seemingly sufficient for that. For male, but not for female participants, grid cell orientation was clustered around the random view of the room experienced at session start. Data suggests that human grid cell orientations can be rather flexible which might be due to the virtuality of the experience. Grid cell orientation might at least for male participants be related to the initial view of an environment. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Heiligkreuztal, Germany 12th Conference of Junior Neuroscientists of Tübingen (NeNA 2011) antopiaA-APape TWolbers johannesJSchultz hhbHHBülthoff meilingerTMeilinger conference GaissertWvBW2011 i-Perception 2011 10 2 8 822 Categorization has traditionally been studied in the visual domain with only a few studies focusing on the abilities of the haptic system in object categorization. During the first years of development, however, touch and vision are closely coupled in the exploratory procedures used by the infant to gather information about objects. Here, we investigate how well shape information can be transferred between those two modalities in a categorization task. Our stimuli consisted of amoeba-like objects that were parametrically morphed in well-defined steps. Participants explored the objects in a categorization task either visually or haptically. Interestingly, both modalities led to similar categorization behavior suggesting that similar shape processing might occur in vision and haptics. Next, participants received training on specific categories in one of the two modalities. As would be expected, training increased performance in the trained modality; however, we also found significant transfer of training to the other, untrained modality after only relatively few training trials. Taken together, our results demonstrate that complex shape information can be transferred efficiently across the two modalities, which speaks in favor of multisensory, higher-level representations of shape. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://imrf.mcmaster.ca/IMRF/ocs3/index.php/imrf/2011/paper/view/430 http://i-perception.perceptionweb.com/journal/I/volume/2/article/ic822 Max Planck Institue for Biological Cybernetics Fukuoka, Japan 12th International Multisensory Research Forum (IMRF 2011) ninagaissertNGaissert swaterkaSWaterkamp vandamLvan Dam hhbHHBülthoff walliCWallraven conference Chuang2011_3 2011 10 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Invited Lecture http://www.liv.ac.uk/psychology/ Max Planck Institute for Biological Cybernetics Liverpool, UK Department of Psychology, University of Liverpool chuangLChuang conference Chuang2011_2 2011 10 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Invited Lecture http://www.tno.nl/content.cfm?context=thema&content=markt_product&laag1=892&laag2=184&laag3=401&item_id=1581&Taal=1 Max Planck Institute for Biological Cybernetics Soesterberg, Netherlands TNO Human Factors chuangLChuang article GaissertBW2011 Acta Psychologica 2011 9 138 1 219-230 Even though human perceptual development relies on combining multiple modalities, most categorization studies so far have focused on the visual modality. To better understand the mechanisms underlying multisensory categorization, we analyzed visual and haptic perceptual spaces and compared them with human categorization behavior. As stimuli we used a three-dimensional object space of complex, parametrically-defined objects. First, we gathered similarity ratings for all objects and analyzed the perceptual spaces of both modalities using multidimensional scaling analysis. Next, we performed three different categorization tasks which are representative of every-day learning scenarios: in a fully unconstrained task, objects were freely categorized, in a semi-constrained task, exactly three groups had to be created, whereas in a constrained task, participants received three prototype objects and had to assign all other objects accordingly. We found that the haptic modality was on par with the visual modality both in recovering the topology of the physical space and in solving the categorization tasks. We also found that within-category similarity was consistently higher than across-category similarity for all categorization tasks and thus show how perceptual spaces based on similarity can explain visual and haptic object categorization. Our results suggest that both modalities employ similar processes in forming categories of complex objects. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sciencedirect.com/science?_ob=MiamiImageURL&_cid=272045&_user=29041&_pii=S0001691811001302&_check=y&_origin=&_coverDate=30-Sep-2011&view=c&wchp=dGLbVBA-zSkzk&md5=8320348e946ed057a766d4d041954797/1-s2.0-S0001691811001302-main.pdf 10.1016/j.actpsy.2011.06.007 ninagaissertNGaissert hhbHHBülthoff walliCWallraven inproceedings SonCFKLLBR2011 2011 9 3039-3046 In this paper, we investigate the maneuverability performance of human teleoperators on multi-robots. First, we propose that maneuverability performance can be assessed by a frequency response function that jointly considers the input force of the operator and the position errors of the multi-robot system that is being maneuvered. Doing so allows us to evaluate maneuverability performance in terms of the human teleoperator's interaction with the controlled system. This allowed us to effectively determine the suitability of different haptic cue algorithms in improving teleoperation maneuverability. Performance metrics based on the human teleoperator's frequency response function indicate that maneuverability performance is best supported by a haptic feedback algorithm which is based on an obstacle avoidance force. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/IROS-2011-Son.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.iros2011.org/ Amato, N.M. IEEE

Piscatawy, NJ, USA

San Francisco, CA, USA IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2011) 978-1-61284-454-1 10.1109/IROS.2011.6048185 chakurtHISon chuangLLChuang antonioAFranchi junsukkimJKim DLee S-WLee hhbHHBülthoff robu_paPRobuffo Giordano poster GaissertWvB2011 Perception 2011 9 40 ECVP Abstract Supplement 134 When humans have to categorize objects they often rely on shape as a deterministic feature. However, shape is not exclusive to the visual modality: the haptic system is also an expert in identifying shapes. This raises the question whether humans store separate modality-dependent shape representations or if one multimodal representation is formed. To better understand how humans categorize objects based on shape we created a set of computer-generated amoeba-like objects varing in defined shape steps. These objects were then printed using a 3D printer to generate tangible stimuli. In a discrimination task and a categorization task, participants either visually or haptically explored the objects. We found that both modalities lead to highly similar categorization behavior indicating that the processes underlying categorization are highly similar in both modalities. Next, participants were trained on special shape categories by using the visual modality alone or by using the haptic modality alone. As expected, visual training increased visual performance and haptic training increased haptic performance. Moreover, we found that visual training on shape categories greatly improved haptic performance and vice versa. Our results point to a shared representation underlying both modalities, which accounts for the surprisingly strong transfer of training across the senses. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v110108 Toulouse, France 34th European Conference on Visual Perception ninagaissertNGaissert swaterkaSWaterkamp vandamLvan Dam isaIBülthoff poster SchultzB2011 Journal of Vision 2011 9 11 11 682 Identifying living moving things in the environment is a priority for animals, as these could be prey, enemies or mates. When the shape of the moving object is hard to see (fog, twilight, great distance, small animal), motion becomes an important cue to detect it. The neural correlates of the detection of an isolated living entity on the basis of its motion are largely unknown. To study this phenomenon, we developed a single-dot stimulus, thus eliminating all possible sources of information about form, spatial arrangement, shape or structure of the object. The dot moved such that it appeared self-propelled, or moved by an external force, or something intermediary according to a small set of parameters. Self-propelled stimuli were perceived as more animate (= more likely to be alive) than the externally-moved stimuli, with a gradual transition occurring in the intermediary morphs following a classic psychometric function (cumulative gaussian). In an fMRI experiment, 20 subjects had to categorize these stimuli into alive and non-alive. A region of the left medial posterior parietal cortex (mPPC) showed BOLD signal correlating with the probability of animacy judgments about the moving dot. While activation in parts of the early visual cortex showed the same response, the mPPC was the only region in which changes in percept had a stronger effect on activation than physical changes in the stimuli. In addition, only the mPPC showed BOLD signal increases when a stimulus was judged to be animate, irrespective of its physical characteristics. This study shows that parts of the early visual cortex but particularly the medial posterior parietal cortex (mPPC) are involved in judging the animacy of an isolated translating visual stimulus, without information about its form. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/11/11/682.abstract Naples, FL, USA 11th Annual Meeting of the Vision Sciences Society (VSS 2011) 10.1167/11.11.682 johannesJSchultz hhbHHBülthoff poster DobsKBSC2011 Perception 2011 9 40 ECVP Abstract Supplement 115 3D facial animation systems allow the creation of well-controlled stimuli to study face processing. Despite this high level of control, such stimuli often lack naturalness due to artificial facial dynamics (eg linear morphing). The present study investigates the extent to which human visual perception can be fooled by artificial facial motion. We used a system that decomposes facial motion capture data into time courses of basic action shapes (Curio et al, 2006 APGV 1 77–84). Motion capture data from four short facial expressions were input to the system. The resulting time courses and five approximations were retargeted onto a 3D avatar head using basic action shapes created manually in Poser. Sensitivity to the subtle modifications was measured in a matching task using video sequences of the actor performing the corresponding expressions as target. Participants were able to identify the unmodified retargeted facial motion above chance level under all conditions. Furthermore, matching performance for the different approximations varied with expression. Our findings highlight the sensitivity of human perception for subtle facial dynamics. Moreover, the action shape-based system will allow us to further investigate the perception of idiosyncratic facial motion using well-controlled facial animation stimuli. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v110293 Toulouse, France 34th European Conference on Visual Perception kdobsKDobs kleinermMKleiner isaIBülthoff johannesJSchultz curioCCurio poster ChuangS2011 2011 9 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.bccn-tuebingen.de/news/article/symposium-imultisensory-perception-and-actioni-96.html Tübingen, Germany Bernstein Cluster D Symposium: Multisensory Perception and Action chuangLLChuang soumanJLSouman poster ChuangBS2011 Perception 2011 9 40 ECVP Abstract Supplement 129 Walking reduces visual speed estimates of optic flow (Souman et al, 2010 Journal of Vision 10(11):14]. Simultaneously, visual background motion can influence the perceived speed of moving objects (Tynan and Sekular, 1975 Vision Research 25 1231–1238; Baker and Graf, 2010 Vision Research 50 193–201). These two effects have been attributed to different subtractive processes, which may help in segregating object motion from self-motion induced optic flow. Here, we investigate how both factors jointly contribute to the perceived visual speed of objects. Participants compared the speed of two central Gabor patches on a ground plane, presented in consecutive intervals, either while standing still or while walking on a treadmill. In half the trials, one of the Gabors was surrounded by a moving random dot pattern, the speed of which matched walking speed. Our results replicated previous findings. A moving surround as well as walking can independently induce a subtractive effect on the perceived speed of the moving center, with the effect size increasing with center speed. However, walking does not affect visual speed estimates of the center when a visual surround is present. These results suggest that the visual input dominates the segregation of object motion from background optic flow. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v110345 Toulouse, France 34th European Conference on Visual Perception chuangLChuang hhbHHBülthoff soumanJSouman poster LeeBAWB2011 Journal of Vision 2011 9 11 11 626 race (the other-race effect or ORE) has been widely cited. Nevertheless, recognizing the identity of a face is a complex task among many others; hence it might be premature to conclude that own-race faces are always easier to process. We investigated whether same-race faces still have a processing advantage over other-race faces when only ethnicity-related information is available to differentiate between faces. We morphed the ethnicity of 20 Caucasians and 20 Asians faces toward their other-race counterpart while keeping their idiosyncratic, identity-related features. Morphing was done at three levels (20%, 50%, and 80% toward the other race). The task for two groups of participants (25 Tübingen and 26 Seoul participants) was to report which face looks more Caucasian (or Asian) after looking at the original face and a morphed face sharing the same idiosyncratic features. Both faces were presented side by side on a computer monitor in one task and sequentially in another task. Importantly, we found no evidence for an ORE in participants’ performance and no performance difference between Tübingen and Seoul participants. Both groups were equally good and equally fast at comparing the ethnicity of two faces regardless of the task, the ethnicity of the faces and the question asked. However, we did find evidence that Seoul and Tübingen participants used different viewing strategies. By investigating their eye-movements in the sequential task, we found that the ethnicity of participants affected fixation durations on specific areas of the face, especially the nose. Also, the type of questions asked and stimulus race altered the pattern of eye movements. These results suggest that although Caucasians and Asians were equally good at dealing with ethnicity information of both races, they might employ different viewing strategies. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/11/11/626.abstract Naples, FL, USA 11th Annual Meeting of the Vision Sciences Society (VSS 2011) 10.1167/11.11.626 ryokyungRKLee isaIBülthoff RAmmann walliCWallraven hhbHHBülthoff poster EsinsBS2011 Journal of Vision 2011 9 11 11 673 An important aspect of face recognition involves the role of featural and configurational information for face perception (e.g. Tanaka and Farah, 1993; Yovel and Duchaine, 2006; Rotshtein et al, 2007). In our study, we investigated the influence of featural and configural information on perceived similarity between faces. Eight pairs of male faces were chosen from our digital face database (http://faces.kyb.tuebingen.mpg.de). The texture and the face shape for both faces in a pair were equalized to create 2 basis faces that differed only in their inner facial features and their configuration, but not in face shape or texture. A computer algorithm allowed to parametrically morph the features, the configuration, or both between the two basis faces of a pair. In our case the morphing was done in 25% steps. 24 participants rated the similarity between pairs of the created faces using a 7-point Likert scale. The faces to compare came from the same basis face pair and could differ either in features or in configuration by 0%, 25%, 50%, 75% or 100%. The results revealed that for the same amount of morphing, faces differing by their features are perceived as less similar than faces differing by their configurations. These findings replicate previous results obtained with less natural or less controlled conditions. Furthermore, we found that linear increases of the difference between both faces in configural or featural information resulted in a nonlinear increase of perceived dissimilarity. An important aspect for the relevance of our results is how natural the face stimuli look like. We asked 24 participants to rate the naturalness of all stimuli including the original faces and the created faces. Despite numerous manipulations, the vast majority of our created face stimuli were rated as natural as the original faces. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/VSS-2011-Esins.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/11/11/673.abstract Naples, FL, USA 11th Annual Meeting of the Vision Sciences Society (VSS 2011) 10.1167/11.11.673 esinsJEsins isaIBülthoff johannesJSchultz poster KaulardFBS2011 Journal of Vision 2011 9 11 11 605 Facial expressions convey both emotional and conversational signals. Research focuses mostly on EMOTIONAL expressions and consistenly finds that these can be reliably distinguished along at least two dimensions: valence and arousal. CONVERSATIONAL expressions, i.e. those conveying mainly communicative meaning, are thought to be less emotional laden. Interestingly, we found evidence pointing towards the same first two underlying dimensions for CONVERSATIONAL expressions when presented dynamically. The question now arises: "Is the emergence of the valence and arousal dimensions for conversational facial expressions based on the emotional content of these expressions?" To answer this, we used questions addressing the emotional (Fontaine et al, 2007) and the conversational content separately. If the distinction of conversational expressions is based on the small amount of emotional information they might contain, we expect emotional content questions to allow a separation of those expressions. Ten native German participants answered a set of 27 questions for 6 emotional and 6 conversational expressions, both presented statically and dynamically, using a rating scale. A dissimilarity matrix was computed for the expressions. To uncover the meaning of the first two underlying dimensions allowing expression differentiation, multidimensional scaling (MDS) was used. Our results show that static and dynamic emotional expressions can only be distinguished by means of emotional content questions. For these emotional expressions, the valence and arousal dimensions emerged in the MDS. In contrast, conversational expressions can be distinguished using conversational content questions but not using emotional content questions. Unlike emotional expressions, dynamic information improved distinction of conversational expressions substantially. We found evidence for valence and arousal to be the underlying dimensions for conversational expressions. Our results suggest that the distinction of conversational expressions along the first two dimensions is based on conversational rather than emotional content. Moreover, different types of facial expressions benefit to different degrees from dynamic information. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/11/11/605.abstract Naples, FL, USA 11th Annual Meeting of the Vision Sciences Society (VSS 2011) 10.1167/11.11.605 kascotKKaulard anaferALFernandez Cruz hhbHHBülthoff johannesJSchultz poster BulthoffSMT2011 Journal of Vision 2011 9 11 11 596 In a previous series of desktop experiments we found no evidence that individuals' height influenced their representation of others' faces or their ability to process faces viewed from above or below (VSS 2009). However, in those experiments face orientation and body height were ambiguous as isolated faces were shown on a computer screen to an observer sitting on a chair. To address those concerns and to specifically examine the influence of learned viewpoint, we created a virtual museum containing 20 full-bodied avatars (statues) that were either sitting or standing. Using a head-mounted display, observers walked through this virtual space three times, approached each statue and viewed them from any horizontal (yaw) angle without time restrictions. We equated eye-level - and thus simulated height – for all participants and restricted their vertical movement to ensure that the faces of sitting avatars were always viewed from above and standing avatars from below. After familiarization, recognition was tested using a standard old-new paradigm in which 2D images of the learnt faces were shown from various viewpoints. Results showed a clear influence of learned viewpoint. Faces that had been learned from above (below) were recognized more quickly and accurately in that orientation than from the opposite orientation. Thus, recognition of specific, newly learned faces appears to be view-dependent in terms of pitch angle. Our failure to find a height effect in our previous study suggests that the variety of views of human faces experienced during a lifetime and possibly the preponderance of conversational situations between humans at close range typically counteracts any influence that body size might have on a person's viewing experience of others' faces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/11/11/596.abstract Naples, FL, USA 11th Annual Meeting of the Vision Sciences Society (VSS 2011) 10.1167/11.11.596 isaIBülthoff sezysSShrimpton mohlerBJMohler ianIMThornton poster KaularddSFBW2011 Perception 2011 9 40 ECVP Abstract Supplement 115 Similarity ratings are used to investigate the cognitive representation of facial expressions. The perceptual and cognitive properties (eg physical aspects, motor expressions, action tendencies) driving the similarity judgments of facial expressions are largely unknown. We examined potentially important properties with 27 questions addressing the emotional and conversational content of expressions (semantic differential). The ratings of these semantic differentials were used as predictors for facial expression similarity ratings. The semantic differential and similarity-rating task were performed on the same set of facial expression videos: 6 types of emotional (eg happy) and 6 types of conversational (eg don’t understand) expressions. Different sets of participants performed the two tasks. Multiple regression was used to predict the similarity data from the semantic differential questions. The best model for emotional expressions consisted of two emotional questions explaining 75% of the variation in similarity ratings. The same model explained significantly less variation for conversational expressions (38%). The best model for those expressions consisted of a single conversational question explaining 44% of the variation. This study shows which properties of facial expressions might affect their perceived similarity. Moreover, our results suggest that different perceptual and cognitive properties might underlie similarity judgments about emotional and conversational expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v110290 Toulouse, France 34th European Conference on Visual Perception kascotKKaulard delarosaSde la Rosa johannesJSchultz anaferALFernandez Cruz hhbHHBülthoff walliCWallraven poster SchultzBP2011 Perception 2011 9 40 ECVP Abstract Supplement 116 Visual perception of moving faces activates parts of the human superior temporal sulcus (STS) whereas static facial information is mainly processed in areas of ventral temporal and lateral occipital cortex. However, recent findings show that the latter regions also respond more to moving faces than to static faces. Here, we investigated the origin of this activation increase, considering the following causes: (i) facial motion per se, (ii) increased static information due to the higher number of frames constituting the movie stimuli, and/or (iii) increased attention towards moving faces. We presented non-rigidly moving faces to subjects in an fMRI scanner. We manipulated static face information and motion fluidity by presenting ordered and scrambled sequences of frames at the original or reduced temporal resolutions. Subjects performed a detection task unrelated to the face stimuli in order to equate attentional influences. Results confirm the increased response due to facial motion in the face-sensitive temporal regions. Activation generally increased with the number of frames but decreased when frames were scrambled. These results indicate that the activation increase induced by moving faces is due to smooth, natural motion and not only to increased static information or attentional modulation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v110303 Toulouse, France 34th European Conference on Visual Perception johannesJSchultz mabrockhausMBrockhaus kpilzKPilz conference Chuang2011 2011 8 29 Many tasks require us to access relevant information from a dynamic visual input. To do so, we move our eyes and bodies as well as manipulate our environments. Unfortunately, experiments on human behavior tend to ignore this fact, often to the detriment of their ecological validity. Our understanding can be better informed by studying how humans actively seek out relevant information in their unrestrained and task-relevant workspaces. I will present several research studies from our lab to demonstrate this point. These studies relate to how humans explore novel objects, unrestrained gaze measurements on wall-sized displays, and the influence of haptic force feedback on the teleoperation of micro unmanned aerial vehicles. Finally, I will introduce our latest research project that targets the implications of a personal air transport system (www.mycopter.eu). http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/D-CIS-Lab-2011-Chuang.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Invited Lecture http://www.d-cis.nl/news/210-colloquium-how-do-we-seek-out-information- Max Planck Institute for Biological Cybernetics Delft, Netherlands D-CIS Lab Colloquium chuangLChuang conference BulthoffAWB2011 i-Perception 2011 7 2 4 355 Faces convey various types of information like identity, ethnicity, sex or emotion. We investigated whether the well-known other-race effect (ORE) is observable when facial information other than identity varies between test faces. First, in a race comparison task, German and Korean participants compared the ethnicity of two faces sharing similar identity information but differing in ethnicity. Participants reported which face looked more Asian or Caucasian. Their behavioral results showed that Koreans and Germans were equally good at discriminating ethnicity information in Asian and Caucasian faces. The nationality of participants, however, affected their eye-movement strategy when the test faces were shown sequentially, thus, when memory was involved. In the second study, we focused on ORE in terms of recognition of facial expressions. Korean participants viewed Asian and Caucasian faces showing different facial expressions for 100ms to 800ms and reported the emotion of the faces. Surprisingly, under all three presentation times, Koreans were significantly better with Caucasian faces. These two studies suggest that ORE does not appear in all recognition tasks involving other-race faces. Here, when identity information is not involved in the task, we are not better at discriminating ethnicity and facial expressions in same race compared to other race faces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://i-perception.perceptionweb.com/journal/I/volume/2/article/ic355 Max Planck Institute for Biological Cybernetics Hong Kong 7th Asia-Pacific Conference on Vision (APCV 2011) ryokyungRKLee isaIBülthoff armannRArmann walliCWallraven hhbHHBülthoff inproceedings SonKCFRLB2011 2011 6 149-154 The use of multiple unmanned aerial vehicles (UAVs) is increasingly being incorporated into a wide range of teleoperation applications. To date, relevant research has largely been focused on the development of appropriate control schemes. In this paper, we extend previous research by investigating how control performance could be improved by providing the teleoperator with haptic feedback cues. First, we describe a control scheme that allows a teleoperator to manipulate the flight of multiple UAVs in a remote environment. Next, we present three designs of haptic cue feedback that could increase the teleoperator's environmental awareness of such a remote environment. These cues are based on the UAVs' i) velocity information, ii) proximity to obstacles, and iii) a combination of these two sources of information. Finally, we present an experimental evaluation of these haptic cue designs. Our evaluation is based on the teleoperator's perceptual sensitivity to the physical environment inhabited by the multiple UAVs. We conclude that a teleoperator's perceptual sensitivity is best served by haptic feedback cues that are based on the velocity information of multiple UAVs. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/WHC-2011-Son.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.haptics2011.org/en/ Jones, L. , M. Harders, Y. Yokokohji IEEE

Piscataway, NJ, USA

Istanbul, Turkey IEEE 2011 World Haptics Conference (WHC 2011) 978-1-4577-0299-0 10.1109/WHC.2011.5945477 chakurtHISon junsukkimJKim chuangLLChuang antonioAFranchi robu_paPRobuffo Giordano DLee hhbHHBülthoff inproceedings GaissertW2011 2011 6 451-456 In this study we want to address the question to what extent the visual and the haptic modalities contribute to the final formation of a complex multisensory perceptual space. By varying three shape parameters a physical shape space of shell-like objects was generated. Participants were allowed to either see or touch the objects or use both senses to explore the objects. Similarity ratings were performed and analyzed using multidimensional scaling (MDS) techniques. By comparing the unimodal perceptual spaces to the multimodal perceptual space we tried to resolve the impact of the visual and the haptic modalities on the combined percept. We found that neither the visual nor the haptic modality dominated the final percept, but rather that the two modalities contributed to the combined percept almost equally. To investigate to which degree these results are transferrable to natural objects, we performed the same visual, haptic, and visuo-haptic similarity ratings and multidimensional scaling analyses using a set of natural sea shells. Again, we found almost equal contributions of the visual and the haptic modalities to the combined percept. Our results suggest that multisensory perceptual spaces are based on a complex combination of object information gathered by different senses. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.haptics2011.org/en/ Jones, L.A. , M. Harders, Y. Yokokohji IEEE

Piscataway, NJ, USA

Istanbul, Turkey IEEE World Haptics Conference (WHC 2011) 978-1-4577-0299-0 10.1109/WHC.2011.5945528 ninagaissertNGaissert walliCWallraven conference WallravenC2011 2011 5 1-2 http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/ICCNS-2011-Wallraven.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://cns.bu.edu/cns-meeting/2011conference.html Boston, MA, USA 15th International Conferece on Cognitive and Neural Systems (ICCNS 2011) walliCWallraven chuangLChuang poster DavidSVE2011_2 2011 4 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.mrc-cbu.cam.ac.uk/socialbrain2011/ Cambridge, UK The Social Brain Workshop 2011 NDavid johannesJSchultz KVogeley AEngel poster DavidSVE2011 Journal of Cognitive Neuroscience 2011 3 23 Supplement 64 A focus on social deficits in autism spectrum disorders (ASD) has, for a long time, obscured the existence of lower-level perceptual abnormalities, although the earliest descriptions of autism included abnormalities in oculomotor behavior and visual attention. More recently, however, abnormalities in perception and attention have increasingly been discussed as influential factors in ASD-specific psychopathology. To this end, the perception of coherent motion in random-dot kinematograms, biological motion in point-light walkers and agency in animated shapes have been investigated in ASD but their relationship remains a matter of debate. It also is unclear whether ASD-related deficits result from difficulties in global motion perception or in processing motion that contains socially relevant signals (e.g. a body and actions). We tested 18 individuals with highfunctioning autism and 16 age-, gender- and IQ-matched control participants, who performed three tasks on a continuum of motion cues and social complexity: (1) low-level translational motion that moved up or down, (2) complex motion of a single dot that moved in an animate or inanimate way, (3) complex motion of two dots that interacted or not. None of these tasks contained objects with human shape and only the first task contained global motion. Participants with autism were selectively impaired in detecting social interaction between two animated shapes (task 3), while low-level motion processing (task 1) and the detection of isolated agents (task 2) were preserved. These findings suggest a distinct social impairment in ASD in understanding interacting agents. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://cogneurosociety.org/annual-meeting/previous-meetings/CNS2011_Program.pdf/view San Francisco, CA, USA 18th Annual Meeting of the Cognitive Neuroscience Society (CNS 2011) NDavid johannesJSchultz KVogeley AEngel book Armann2011 2011 167 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.logos-verlag.de/cgi-bin/engbuchmid?isbn=2900&lng=deu&id= Logos-Verlag

Berlin, Germany

MPI Series in Biological Cybernetics ; 29 978-3-8325-2900-0 armannRArmann book Gaissert2011 2011 204 Das wichtigste Werkzeug des Menschen sind seine Hände. Obwohl dieses Sprichwort schon sehr alt ist, ist nur wenig darüber bekannt, wie und was der Mensch wahrnimmt, wenn er Objekte in die Hand nimmt und betastet. Wie wird die ertastete Form eines Objektes im Gehirn abgespeichert? Ist die haptische Repräsentation ähnlich zu der, der visuellen Wahrnehmung? Entsteht sogar eine multisensorische, und somit gemeinsame, Repräsentation? Diese fundamentalen Fragen bilden den Hintergrund der vorliegenden Dissertation. Die hier dargestellten Experimente zeigen, dass der Mensch sehr ähnliche perzeptuelle Räume generiert, wenn komplexe Formen eines parametrisch definierten Objektraumes visuell oder haptisch exploriert werden. Um dies zu zeigen, wurde zuerst ein dreidimensionaler Objektraum muschelähnlicher Objekte generiert, welche in drei Formparametern variieren. Versuchspersonen wurden in den visuellen Versuchen Fotos oder virtuelle Rekonstruktionen der Objekte gezeigt, während in den haptischen Versuchen 3D Plastikmodelle der Objekte, generiert mit einem 3D Drucker, mit verbundenen Augen betastet wurden. In einer ersten Reihe von Experimenten bewerteten die Versuchspersonen die Ähnlichkeit zweier, nacheinander gezeigter, Objekte. Mit diesen Ähnlichkeitsbewertungen und mit Hilfe des Verfahrens der multidimensionalen Skalierung wurden die perzeptuellen Räume beider Modalitäten visualisiert. Überraschenderweise konnten die Versuchspersonen die Topologie des Objektraumes korrekt nachbilden, unabhängig davon, ob sie die Objekte gesehen oder betastet hatten. Weiterhin zeigten die Ergebnisse, dass der visuelle und der haptische perzeptuelle Raum fast identisch waren. Als nächstes wurden drei Kategorisierungsexperimente durchgeführt. Obwohl Kategorisierung allein durch den Tastsinn eher eine ungewöhnliche Aufgabe ist, konnte sie genauso gut gelöst werden, wie wenn die Versuchspersonen die Objekte sehen konnten. Anschließend wurden die perzeptuellen Räume beider Modalitäten mit den Ergebnissen der Kategorisierungsexperimente verglichen. Für alle Kategorisierungsexperimente und für beide Modalitäten war die wahrgenommene Ähnlichkeit zwischen Objekten einer Kategorie höher, als die Ähnlichkeit zweier Objekte aus unterschiedlichen Kategorien. Das heißt, dass, sowohl visuell als auch haptisch, Objekte in einer Kategorie zusammengruppiert wurden, die als sehr ähnlich wahrgenommen wurden. Um zu untersuchen, inwieweit die auf den computergenerierten Objekten basierenden Ergebnisse auf natürliche Objekte übertragbar sind, wurde eine Sammlung von Muscheln und Salzwasserschnecken erstellt. Mit diesen wurden, wie oben beschrieben, Ähnlichkeitsbewertungen durchgeführt und mittels multidimensionaler Skalierung die perzeptuellen Räume visualisiert. Wiederum waren der visuelle und der haptische perzeptuelle Raum fast identisch. Interessanterweise konnte man in beiden Räumen eine Gruppenbildung erkennen, weshalb auch hier drei Kategorisierungsexperimente durchgeführt wurden. Obwohl die Muscheln in einer Vielzahl an Objektmerkmalen variierten, z.B. Form, Farbe, Muster etc., konnten die Versuchspersonen diese Aufgabe ohne Mühe lösen, auch wenn sie die Objekte nur betasten durften. Zusätzlich konnte die Gruppenbildung, die schon in den perzeptuellen Räumen erkennbar war, die Kategorisierungsergebnisse richtig vorhersagen. Zusammengenommen weisen diese Ergebnisse darauf hin, dass die visuelle und die haptische Repräsentation von Objekten sehr eng miteinander verknüpft sein müssen. Zusätzlich liefern die Experimente Hinweise darauf, dass die gleichen Prozesse genutzt werden, wenn Ähnlichkeiten zwischen Objekten wahrgenommen werden, oder Objekte kategorisiert werden, egal ob die Objekte visuell oder haptisch exploriert werden. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.logos-verlag.de/cgi-bin/engbuchmid?isbn=2794&lng=eng&id= Logos-Verlag

Berlin, Germany

MPI Series in Biological Cybernetics ; 26 978-3-8325-2794-5 ninagaissertNGaissert thesis Chuang2011_5 2011 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.logos-verlag.de/cgi-bin/buch/isbn/2842 Max Planck Institute for Biological Cybernetics, Tübingen, Germany PhD chuangLLChuang poster 7068 2010 11 40 581.20 While face categorization is a fundamental cognitive ability of human and non-human primates, its neural basis remain poorly understood. Using a new morphing technique, we created realistic three-dimensional morphed faces that linearly span the continuum between humans and monkeys (“species” continuum). Extensive categorization and discrimination experiments in human observers show that humans perceive the “species” continuum categorically. Moreover, the position of the categorical boundary is shifted from the center towards the human end of the continuum, suggesting a higher sensitivity to changes near the own-species prototype. We presented a subset of these faces to human subjects in a block-design fMRI experiment to record BOLD signals from the temporal lobe while participants performed an unrelated task at fixation. We applied a multivariate approach based on (Pearson) correlations to compute the difference between activity patterns elicited by faces along the continuum. Using this method, we looked for a categorical representation in face selective areas previously defined using an independent, standard "Face-localizer" experiment. Consistent with the psychophysical results, we found a categorical response with a bias towards the human end of the stimulus continuum in the activation patterns of the left human STS. In addition, activation in human ventral temporal cortex was most sensitive to deviations from the human prototype. To look for similar effects in monkeys, we applied an equivalent multivariate approach to analyze extracellular signals from a population of neurons recorded from the STS of two macaque monkeys while they fixated at the same type of faces. Additionally, the position of the perceptual category boundary was determined with a preferential-looking-time experiment. In both behavioral and neuronal monkey data, we found a categorical representation of the continuum, but in this case, with a bias towards the monkey end of the continuum. Our results demonstrate the neural basis of categorical representation of a facial attribute in the human and non-human primate brain. Together, our findings suggest that experience can lead to significant shifts in category boundary for face stimuli. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Bülthoff http://www.sfn.org/am2010/index.aspx?pagename=abstracts_main Biologische Kybernetik Max-Planck-Gesellschaft San Diego, CA, USA 40th Annual Meeting of the Society for Neuroscience (Neuroscience 2010) en sigalaGRSigala Alanis johannesJSchultz nikosNKLogothetis gregorGRainer poster SchultzBP2011_2 2010 11 40 393.10 Visual perception of moving faces activates parts of the human superior temporal sulcus (STS) whereas static facial information is mainly processed in areas of ventral temporal and lateral occipital cortex. However, recent findings show that the latter regions also respond more to moving faces than to static faces (Schultz and Pilz, 2009). This study investigated the origin of this activation increase. We considered the following causes: (1) facial motion per se (2) increased static information due to the higher number of frames constituting the movie stimuli, and/or (3) increased attention towards moving faces, which would increase the response in face-sensitive areas through top-down modulation. We presented non-rigidly moving faces to participants lying in an fMRI scanner. We manipulated static face information and fluidity of the motion in the stimuli by presenting ordered and scrambled sequences of frames at temporal resolutions of 25 frames per second (fps) which were perceived as fluid motion when ordered, but as very non-fluid when scrambled, 12.5 fps (still perceived as fluid when ordered) and 5 fps (significantly less fluid when ordered, with smallest effect of scrambling). To control the influence of attention, subjects were asked to perform a target detection task that was unrelated to the face stimuli (one-back matching task on a stream of letters presented at fixation). Results confirm the increased activation induced by facial motion in the face-sensitive fusiform and superior temporal regions. A purely attention-based effect can be ruled out given that the task performance was far from ceiling performance and equal across conditions. While activation generally increased with the number of frames, a significant reduction of activation was observed due to frame-scrambling the stimuli. These results indicate that the activation increase induced by moving faces is due to the motion of the stimulus (i.e. temporal order of the frames) and not only to increased static information or attentional modulation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sfn.org/am2010/index.aspx?pagename=final_program San Diego, CA, USA 40th Annual Meeting of the Society for Neuroscience (Neuroscience 2010) johannesJSchultz mabrockhausMBrockhaus kpilzKPilz conference KaulardWdB2010 2010 10 11 16 Most research on facial expressions focuses on static, ’emotional’ expressions. Facial expressions, however, are also important in interpersonal communication (’conversational’ expressions). In addition, communication is a highly dynamic phenomenon and previous evidence suggests that dynamic presentation of stimuli facilitates recognition. Hence, we examined the categorization of emotional and conversational expressions using both static and dynamic stimuli. In a between-subject design, 40 participants were asked to group 55 different facial expressions (either static or dynamic) of ten actors in a free categorization task. Expressions were to be grouped according to their overall similarity. The resulting confusion matrix was used to determine the consistency with which facial expressions were categorized. In the static condition, emotional expressions were grouped as separate categories while participants confused conversational expressions. In the dynamic condition, participants uniquely categorized basic and sub-ordinate emotional, as well as several conversational facial expressions. Furthermore, a multidimensional scaling analysis suggests that the same potency and valence dimensions underlie the categorization of both static and dynamic expressions. Basic emotional expressions represent the most effective categories when only static information is available. Importantly, however, our results show that dynamic information allows for a much more fine-grained categorization and is essential in disentangling conversational expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.neuroschool-tuebingen-nena.de/fileadmin/user_upload/Dokumente/neuroscience/AbstractbookNeNa2010u.pdf Heiligkreuztal, Germany 11th Conference of Junior Neuroscientists of Tübingen (NeNa 2010) kascotKKaulard walliCWallraven delarosaSde la Rosa hhbHHBülthoff article 6643 Journal of Vision 2010 9 10 11:2 1-20 In this study, we show that humans form highly similar perceptual spaces when they explore complex objects from a parametrically defined object space in the visual and haptic domains. For this, a three-dimensional parameter space of well-defined, shell-like objects was generated. Participants either explored two-dimensional pictures or three-dimensional, interactive virtual models of these objects visually, or they explored three-dimensional plastic models haptically. In all cases, the task was to rate the similarity between two objects. Using these similarity ratings and multidimensional scaling (MDS) analyses, the perceptual spaces of the different modalities were then analyzed. Looking at planar configurations within this three-dimensional object space, we found that active visual exploration led to a highly similar perceptual space compared to passive exploration, showing that participants were able to reconstruct the complex parameter space already from two-dimensional pictures alone. Furthermore, we found that visual and haptic perceptual spaces had virtually identical topology compared to that of the physical stimulus space. Surprisingly, the haptic modality even slightly exceeded the visual modality in recovering the topology of the complex object space when the whole three-dimensional space was explored. Our findings point to a close connection between visual and haptic object representations and demonstrate the great degree of fidelity with which haptic shape processing occurs. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/10/11/2.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft en 10.1167/10.11.2 ninagaissertNGaissert walliCWallraven hhbHHBülthoff inproceedings 6656 PRICAI 2010: Trends in Artificial Intelligence 2010 9 1-3 Research in learning algorithms and sensor hardware has led to rapid advances in artificial systems over the past decade. However, their performance continues to fall short of the efficiency and versatility of human behavior. In many ways, a deeper understanding of how human perceptual systems process and act upon physical sensory information can contribute to the development of better artificial systems. In the presented research, we highlight how the latest tools in computer vision, computer graphics, and virtual reality technology can be used to systematically understand the factors that determine how humans perform in realistic scenarios of complex task-solving. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/PRICAI-62300001%20(1)_6656[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.pricai2010.org/default.asp Zhang, B.-T. , M. A. Orgun Springer

Berlin, Germany

PRICAI 2010: Trends in Artificial Intelligence Biologische Kybernetik Max-Planck-Gesellschaft Daegu, South Korea 11th Pacific Rim International Conference on Artificial Intelligence en 978-3-642-15246-7 10.1007/978-3-642-15246-7_1 hhbHHBülthoff chuangLLChuang inproceedings ChuangBBF2010 2010 8 347-348 Motivation -- Natural gaze involves the coordinated movements of eye, head and torso. This allows access to a wide field of view, up to a range of 260° (Chen, Solinger, Poncet & Lancet, 1999). The recent increase in large displays places a demand on being able to track a mobile user's gaze over this extensive range. Research approach -- We developed an extensible system for measuring the gaze of users on wall-sized displays. Our solution combines the inputs of a conventional head-mounted eyetracker (Eyelink2©, SR Research) and motion-capture system (Vicon MX©, Vicon), to provide real-time measurements of a mobile user's gaze in 3D space. Findings/Design -- The presented system serves as a single platform for studying user behavior across a wide range of tasks: single-step saccade shifts, free-viewing of natural scenes, visual search and gaze-assisted user interfaces. Importantly, it allows eye- and head-movements to be separately measured without compromising the accuracy of combined gaze measurements. Take away message -- Unrestrained gaze movements on a large display can be accurately measured by suitably combining the inputs of conventional eye- and body-tracking hardware. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://ecce2010.tudelft.nl/ Neerincx, W. , W-P Brinkman ACM Press

New York, NY, USA

Delft, Netherlands 28th Annual European Conference on Cognitive Ergonomics (ECCE '10) 978-1-60558-946-6 10.1145/1962300.1962379 chuangLLChuang biegH-JBieg hhbHHBülthoff rolandRWFleming poster 6606 Perception 2010 8 39 ECVP Abstract Supplement 35 Video-based eye-trackers are typically calibrated by instructing participants to fixate a series of dots, the physical locations of which are known to the system. Unfortunately, this procedure does not verify if fixation has actually occurred at the desired locations. This limitation can be remedied by requiring participants to perform a simple visual discrimination task at each location, thus mandating accurate fixation. Still, it remains an open question whether this modification could affect fixation accuracy. In the current study, we compared the accuracy of fixations that were performed with a visual discrimination task and those without such a requirement. Participants either identified the orientation of a small Landolt C (size = 0.1°) or fixated a similar probe without performing the task. Results indicate that participants fixated equally well in both tasks (mean diff. of abs. error = 0.01°, Bayes factor B01 = 4.0 with JZS prior, see [Rouder et al., 2009, Psychonomic Bulletin &am p;am p;am p; R eview, 16(2), 225-237]). Given this, we propose the implementation of this visual discrimination task to eye-tracking calibration protocols as it elicits verifiable fixations without compromising fixation accuracy. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v100606 Biologische Kybernetik Max-Planck-Gesellschaft Lausanne, Switzerland 33rd European Conference on Visual Perception en biegH-JBieg chuangLLChuang hhbHHBülthoff poster 6787 Perception 2010 8 39 ECVP Abstract Supplement 90 Generally, faces of one’s own ethnicity are better remembered than faces of another race. The mechanisms of this other race effect (ORE) are still unresolved. The present study investigates whether expertise for own-race results in ORE in a discrimination task when only race-specifying information varies between faces, with no interference of identity change and no memory load. If expertise is an important factor for ORE, Caucasian participants, for example, should better discriminate between two Caucasian faces presented side by side than between two Asian faces. We tested participants in Seoul and Tübingen with pairs of Asian or Caucasian faces. Their task was to tell which face of the pair was either more Asian or more Caucasian. Although we found that Asian face pairs were unexpectedly but consistently better discriminated than Caucasian faces, this Asian advantage did not differ between both city groups. Our results show furthermore that Seoul and Tübingen participants’ discrimination performance was similar for Asian and Caucasian faces. These findings suggests that when there is no memory component involved in the task and when face appearance only differs in race-specifying information, own-race expertise does not result in better performance for own-race faces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v100038 Biologische Kybernetik Max-Planck-Gesellschaft Lausanne, Switzerland 33rd European Conference on Visual Perception en isaIBülthoff ryokyungRKLee walliCWallraven hhbHHBülthoff poster Schultz2010 Perception 2010 8 39 ECVP Abstract Supplement 19 We previously developped stimuli allowing parametric control over the percept of animacy evoked by the movements of a single object, without contribution from spatial arrangement, shape or structure of the object (Schultz and Dopjans, 2008 Perception 35 ECVP Supplement, 154). As observers tend to follow the stimulus with their eyes while performing animacy judgments, we quantified these eye movements in the present study (Experiment 1). In Experiment 2, we tested the importance of eye movements and attention for task performance by forcing subjects to fixate while judging animacy. In Experiment 3, attentional resources were further reduced by asking subjects to perform a secondary task at fixation while judging animacy. Experiment 1 showed that the distance between eye fixations and the stimulus increased with changes in animacy, compatible with a greater difficulty in following animate-looking stimuli. Combined results across experiments show that the strength of the changes in percept tends to be reduced with fixed gaze and is significantly decreased in the dual-task setting. In the latter, the greatest disruption in stimulus processing appears to result from detecting and reporting the fixation targets rather than just splitting attentional resources. These results suggest that at least partially sustained attention is required for animacy judgments about our single moving dot stimulus. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v100581 Lausanne, Switzerland 33rd European Conference on Visual Perception johannesJSchultz poster 6751 Perception 2010 8 39 ECVP Abstract Supplement 54 Mirror Neurons (MN) have been suggested to be the supporting neural mechanism for action recognition and understanding. However, there is a current debate about the localization of MN in humans. Functional magnetic resonance imaging (fMRI) studies using repetition suppression (RS) paradigms for the identification of MN provide mixed results. Studies supporting the existence of MN restricted their analysis to a-priori candidate regions, whereas studies that failed to find evidence used non-object-directed actions. In the present fMRI study, we tackled these limitations by using object-directed actions in a RS paradigm and performing a wholebrain analysis. Subjects observed and executed simple grasping movements differing only in their goal-directness (grasping a button vs. grasping beside it). MN areas should be (1) more activated by goal-directed actions and (2) exhibit RS between execution and observation of the same action. The analysis revealed three significant cortical clusters in the right anterior intraparietal sulcus (aIPS), right primary somatosensory cortex and left premotor cortex that show these characteristics. While the aIPS has been reported before as a possible region for MN, the other two clusters haven’t been associated with MN directly yet using RS paradigms. We discuss the potential contribution of these regions to object-directed actions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Department MRZ http://www.perceptionweb.com/abstract.cgi?id=v100476 Biologische Kybernetik Max-Planck-Gesellschaft Lausanne, Switzerland 33rd European Conference on Visual Perception en friederFSchillinger delarosaSde la Rosa johannesJSchultz KUludag conference 6740 Perception 2010 8 39 ECVP Abstract Supplement 157 Most research on facial expressions focuses on static, ‘emotional’ expressions. Facial expressions, however, are also important in interpersonal communication (‘conversational’ expressions). In addition, communication is a highly dynamic phenomenon and previous evidence suggests that dynamic presentation of stimuli facilitates recognition. Hence, we examined the categorization of emotional and conversational expressions using both static and dynamic stimuli. In a between-subject design, 40 participants were asked to group 55 dierent facial expressions (either static or dynamic) of ten actors in a free categorization task. Expressions were to be grouped according to their overall similarity. The resulting confusion matrix was used to determine the consistency with which facial expressions were categorized. In the static condition, emotional expressions were grouped as separate categories while participants confused conversational expressions. In the dynamic condition, participants uniquely categorized basic and sub-ordinate emotional, as well as several conversational facial expressions. Furthermore, a multidimensional scaling analysis suggests that the same potency and valence dimensions underlie the categorization of both static and dynamic expressions. Basic emotional expressions represent the most eective categories when only static information is available. Importantly, however, our results show that dynamic information allows for a much more fine-grained categorization and is essential in disentangling conversational expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v100478 Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics Lausanne, Switzerland 33rd European Conference on Visual Perception en kascotKKaulard walliCWallraven delarosaSde la Rosa hhbHHBülthoff conference 6726 Perception 2010 8 39 ECVP Abstract Supplement 155 Recent models of face perception often adopt a framework in which faces are represented as points in a multidimensional space, relative to the average face that serves as a norm. Faces share many visual properties and could be encoded in one face space against one single norm. However, certain face properties may result in grouping of similar faces. How faces might be ‘subclassified’ in face space remains thus to be determined. We studied the processing of faces of different races, using high-level aftereffects, where exposure to one face systematically distorts the perception of a subsequently viewed face towards the ‘opposite’ identity in face space. We measured identity aftereffects for adapt-test pairs that were opposite race-specific (Asian and Caucasian) averages and pairs that were opposite a ‘generic’ average (both races morphed together). Aftereffects were larger for race-specific than for generic anti-faces. Since adapt-test pairs that lie opposite each other in face space generate larger aftereffects than non-opposite test pairs, these results suggest that Asian and Caucasian faces are coded using race-specific norms. Moreover, identification (at low identity strength) of the target faces was easier around the race-specific norms than around the generic norm, indicating that norms also have a functional role in face processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v100426 Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics Lausanne, Switzerland 33rd European Conference on Visual Perception en armannRGMArmann LJeffery AJCalder isaIBülthoff GRhodes poster 6818 2010 6 2010 93 Categorization of faces is fundamental for social interactions of primates. To understand its neural basis, we investigate how human and monkey face categories are represented in both the human and non-human primate brain. As stimuli, we use realistic three-dimensional morphed faces that linearly span the continuum between humans and monkeys (Fig. 1A). Extensive behavioral tests in both species revealed categorical perception with a shift of the categorical boundary towards the own species (Fig. 1B). This suggests that both species perceive the same stimulus continuum in a fundamentally different way. During a fixation task, we recorded from the temporal lobe extracellular signals in monkeys and BOLD signals in humans. To analyze the data, we used a multivariate pattern classifier approach based on Support Vector Machines and correlations. Consistent with the psychophysical results, we found an "own-species" bias in the categorical representation of human and monkey faces at the level of single neurons as well as in the population response in the inferior temporal lobe of the monkey. (Fig. 1C). Symmetrically, we found a categorical response with an ownspecies bias in the activation patterns of the left human STS. In addition, human ventral temporal cortex showed a higher sensitivity for human faces. Our results are the first to demonstrate the neural basis of categorical representation of a facial attribute in the primate brain. In addition, our data show that both psychophysical and neuronal data can show categorical boundary shifts indicative of the behavioral relevance of prototypical categories. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis Department Bülthoff http://www.areadne.org/2010/home.html Hatsopoulos, N. G., S. Pezaris Biologische Kybernetik Max-Planck-Gesellschaft Santorini, Greece AREADNE 2010: Research in Encoding And Decoding of Neural Ensembles en sigalaRSigala johannesJSchultz nikosNKLogothetis gregorGRainer poster SchultzB2010 2010 6 16 194 MT-PM 62 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.humanbrainmapping.org/i4a/pages/index.cfm?pageid=3342 Barcelona, Spain 16th Annual Meeting of the Organisation for Human Brain Mapping (HBM 2010) johannesJSchultz hhbHHBülthoff conference Bulthoff2010 2010 6 16 Wir untersuchten die Wechselwirkung von identittäts- und geschlechtsspezifischen Informationen in der Gesichtswahrnehmung. In Experiment 1 war es die Aufgabe der Probanden, die Originalversion eines bekannten Gesichts neben einer Anzahl modizierter Versionen dieses Gesichts auszuwählen. Diese Aufgabe war leichter, wenn das Originalgesicht zusammen mit identitätsmodizierten statt mit geschlechtsmodizierten Versionen des Originalgesichts präsentiert wurde, was den Schluss nahelegt, dass geschlechtsspezische Informationen nicht akkurat im Gedächtnis abgelegt werden. In Experiment 2, modizierten wir das Geschlecht einer Reihe von Gesichtern, indem wir weibliche Gesichter in männliche Gesichter transformierten. Probanden hatten grössere Schwierigkeiten, diese geschlechtsmodifizierten Gesichter als männliche Gesichter zu klassizieren, wenn ihnen das Originalgesicht bekannt war. Im Gegensatz zum klassischen Modell der Gesichtsverarbeitung nach Bruce & Young (1986), weisen unsere Daten darauf hin, dass bei Gesichtern geschlechtspezifische Informationen nicht unabhängig von identitätsspezischen Informationen verarbeitet werden. Zusammenfassend können wir sagen, dass unser visuelles System nicht unbedingt darauf angelegt zu sein scheint, perfekte Modelle auch bekannter Gesichter zu speichern { besonders nicht im Hinblick auf das Geschlecht. Vermutlich ist eine akkurate Geschlechtsinformation nicht notwendig - vor allem da sie nur aus den beiden Klassen männlich und weiblich besteht - so dass identitätsspezfiische Informationen geschlechtsspezische Informationen dominieren, auch wenn dies nicht zweckmässig ist. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://tagung.dgpa.de/fileadmin/files/ABSTRACTBAND_web.pdf Greifswald, Germany 36. Tagung "Psychologie und Gehirn" isaIBülthoff inproceedings PastraWSVK2010 2010 5 3031-3036 Natural language use, acquisition, and understanding takes place usually in multisensory and multimedia communication environments. Therefore, for one to model language in its interaction and integration with sensorimotor experiences, one needs a representative corpus of such interplay. In this paper, we will present the first corpus of language use and sensorimotor experience recordings in everyday human:human interaction, in which spontaneous language communication has been recorded along with corresponding multiview video recordings, recordings of 3D full body kinematics, and 3D tracking of objects in focus. It is a twelve-hour corpus which comprises of six everyday human:human interaction scenes, each one performed 3 times by 4 different English-speaking couples (interaction between a male and a female actor), each couple acting each scene in two settings: a fully naturalistic setting in which 5-camera multi-view video recordings take place, and a high-tech setting, with full body motion capture for both individuals, a 2-camera multiview video recording, and 3D tracking of focus objects. The corpus has been developed within an EU-funded cognitive systems research project, POETICON (http://www.poeticon.eu), and represents a new type of language resources for cognitive systems. Namely, a corpus that reveals the dynamic role of language in its interplay with sensorimotor experiences and which allows one to computationally model this interplay. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/LREC-2010-Pastra.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.lrec-conf.org/lrec2010/ Calzolari , N. , K. Choukri, B. Maegaard, J. Mariani, J. Odijk, S. Piperidis, M. Rosner, D. Tapias ELRA

Paris, France

Valletta, Malta Seventh International Conference on Language Resources and Evaluation (LREC 2010) 2-9517408-6-7 KPastra walliCWallraven mschultzeMSchultze AVatakis kascotKKaulard poster 6739 Journal of Vision 2010 5 10 7 606 Facial expressions form one of the most important and powerful communication systems of human social interaction. They express a large range of emotions but also convey more general, communicative signals. To date, research has mostly focused on the static, emotional aspect of facial expression processing, using only a limited set of “generic” or “universal” expression photographs, such as a happy or sad face. That facial expressions carry communicative aspects beyond emotion and that they transport meaning in the temporal domain, however, has so far been largely neglected. In order to enable a deeper understanding of facial expression processing with a focus on both emotional and communicative aspects of facial expressions in a dynamic context, it is essential to first construct a database that contains such material using a well-controlled setup. We here present the novel MPI facial expression database, which contains 20 native German participants performing 58 expressions based on pre-defined context scenarios, making it the most extensive database of its kind to date. Three experiments were performed to investigate the validity of the scenarios and the recognizability of the expressions. In Experiment 1, 10 participants were asked to freely name the facial expressions that would be elicited given the scenarios. The scenarios were effective: 82% of the answers matched the intended expressions. In Experiment 2, 10 participants had to identify 55 expression videos of 10 actors. We found that 34 expressions could be identified reliably without any context. Finally, in Experiment 3, 20 participants had to group the 55 expression videos of 10 actors based on similarity. Out of the 55 expressions, 45 formed consistent groups, which highlights the impressive variety of conversational expressions categories we use. Interestingly, none of the experiments found any advantage for the universal expressions, demonstrating the robustness with which we interpret conversational facial expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/10/7/606 Biologische Kybernetik Max-Planck-Gesellschaft Naples, FL, USA 10th Annual Meeting of the Vision Sciences Society (VSS 2010) en 10.1167/10.7.606 kascotKKaulard walliCWallraven dwcDWCunningham hhbHHBülthoff poster 6728 Journal of Vision 2010 5 10 7 706 High-level perceptual aftereffects have revealed that faces are coded relative to norms that are dynamically updated by experience. The nature of these norms and the advantage of such a norm-based representation, however, are not yet fully understood. Here, we used adaptation techniques to get insight into the perception of faces of different race categories. We measured identity aftereffects for adapt-test pairs that were opposite a race-specific average and pairs that were opposite a ‘generic’ average, made by morphing together Asian and Caucasian faces. Aftereffects were larger following exposure to anti-faces that were created relative to the race-specific (Asian and Caucasian) averages than to anti-faces created using the mixed-race average. Since adapt-test pairs that lie opposite to each other in face space generate larger identity aftereffects than non-opposite test pairs, these results suggest that Asian and Caucasian faces are coded using race-specific norms. We also found that identification thresholds were lower when targets were distributed around the race-specific norms than around the mixed-race norm, which is also consistent with a functional role for race-specific norms. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/10/7/706.abstract Biologische Kybernetik Max-Planck-Gesellschaft Naples, FL, USA 10th Annual Meeting of the Vision Sciences Society (VSS 2010) en 10.1167/10.7.706 armannRGMArmann LJeffery ACalder isaIBülthoff GRhodes inproceedings 6292 Proceedings of the Haptics Symposium 2010 2010 4 35-42 Studies concerning how the brain might represent objects by means of a perceptual space have primarily focused on the visual domain. Here we want to show that the haptic modality can equally well recover the underlying structure of a physical object space, forming a perceptual space that is highly congruent to the visual perceptual space. By varying three shape parameters a physical shape space of shell-like objects was generated. Sighted participants explored pictures of the objects while blindfolded participants haptically explored 3D printouts of the objects. Similarity ratings were performed and analyzed using multidimensional scaling (MDS) techniques. Visual and haptic similarity ratings highly correlated and resulted in very similar visual and haptic MDS maps. To investigate to which degree these results are transferrable to natural objects, we performed the same visual and haptic similarity ratings and multidimensional scaling analyses using a set of natural sea shells. Again, we found very similar per ceptual spaces in the haptic and visual domain. Our results suggest that the haptic modality is capable of surprisingly acute processing of complex shape. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Haptics2010-Gaissert_6292[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.hapticssymposium.org/next_conference.html Colgate, J. E., S. Lederman, D. Prattichizzo IEEE

Piscataway, NJ, USA

Biologische Kybernetik Max-Planck-Gesellschaft Waltham, MA, USA IEEE Haptics Symposium 2010 en 978-1-424-46821-8 10.1109/HAPTIC.2010.5444683 ninagaissertNGaissert walliCWallraven article 6402 Current Biology 2010 3 20 6 R269-R271 Recent advances in neuroimaging allow mental states to be inferred from non-invasive data. In a new study, memories of complex events were successfully decoded solely from imaged activation in a memory-related brain structure. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6VRT-4YNKHPX-D-4&_cdi=6243&_user=29041&_pii=S0960982210001314&_orig=search&_coverDate=03%2F23%2F2010&_sk=999799993&view=c&wchp=dGLzVtz-zSkWz&md5=91beb337f50434cb758048e520c0abb5&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.cub.2010.02.001 johannesJSchultz inproceedings 6246 Proceedings of the Symposium on Eye Tracking Research and Applications (ETRA 2010) 2010 3 89-92 Selecting a graphical item by pointing with a computer mouse is a ubiquitous task in many graphical user interfaces. Several techniques have been suggested to facilitate this task, for instance, by reducing the required movement distance. Here we measure the natural coordination of eye and mouse pointer control across several search and selection tasks. We find that users automatically minimize the distance to likely targets in an intelligent, task dependent way. When target location is highly predictable, top-down knowledge can enable users to initiate pointer movements prior to target fixation. These findings ques-tion the utility of existing assistive pointing techniques and suggest that alternative approaches might be more effective. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/ETRA2010-Bieg_6246[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://etra.cs.uta.fi/ Morimoto, C. H., H. Istance, A. Hyrskykari, Q. Ji ACM Press

New York, NY, USA

Biologische Kybernetik Max-Planck-Gesellschaft Austin, TX, USA Symposium on Eye Tracking Research and Applications (ETRA 2010) en 10.1145/1743666.1743688 biegH-JBieg chuangLLChuang rolandRWFleming HReiterer hhbHHBülthoff inproceedings 6293 Cognitive shape processing: papers from the AAAI Spring Symposium 2010 3 2-7 In this study we show that humans form very similar perceptual spaces when they explore parametrically-defined shell-shaped objects visually or haptically. A physical object space was generated by varying three shape parameters. Sighted participants explored pictures of these objects while blindfolded participants haptically explored 3D printouts of the objects. Similarity ratings were performed and analyzed using multidimensional scaling (MDS) techniques. Visual and haptic similarity ratings highly correlate and resulted in very similar visual and haptic MDS maps providing evidence for one shared perceptual space underlying both modalities. To investigate to which degree these results are transferrable to natural objects, we performed the same visual and haptic similarity ratings and multidimensional scaling analyses using a set of natural sea shells. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/AAAI-2010-Gaissert_6293[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.spatial-cognition.de/CSP/ Barkowsky, T. , S. Bertel, C. Hölscher, T. F. Shipley AAAI Press

Menlo Park, CA, USA

Biologische Kybernetik Max-Planck-Gesellschaft Stanford, CA, USA AAAI 2010 Spring Symposium on Cognitive Shape Processing en ninagaissertNGaissert ulrichsKUlrichs walliCWallraven conference ArmannR2009 2009 11 9 10 High-level perceptual aftereffects have revealed that faces are coded relative to norms, supposedly via some sort of opponent coding mechanism that is dynamically updated by experience. The nature of these norms and the advantage of such a norm-based representation, however, are not yet fully understood. Here, we used high-level adaptation techniques to get insight into the perception of faces of different race categories. We compared the size of identity aftereffects (AEs) for pairs of adapt and test faces that were taken from different morph trajectories, based on potential norms for Asian and Caucasian faces. Larger aftereffects were found following exposure to anti-faces created relative to averages of the race of the target identities, than to anti-faces created using a generic average. Since adapt-test pairs lying opposite to each other in face space generate larger identity AEs than non-opposite test pairs, this suggests that Asian and Caucasian faces are coded using race-specific norms, rather than a generic one. Moreover, we find that identification performance is better for face morphs that are created using these race-specific norms, independent of their actual identity strength. To our knowledge, this is the first evidence for a functional benefit of norms in face recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.neuroschool-tuebingen-nena.de/ Ellwangen, Germany 10th Conference of Junior Neuroscientists of Tübingen (NeNa 2009) armannRArmann GRhodes conference KaulardWCB2009 2009 11 10 11 Compared to other species, humans have developed highly sophisticated communication systems for social interaction. One of the most important communication systems is based on facial expressions, which are both used for expressing emotions and conveying intentions. Starting already at birth, humans are trained to process faces and facial expressions, resulting in a high degree of perceptual expertise for face perception and social communication. To date, research has mostly focused on the emotional aspect of facial expression processing, using only a very limited set of „generic“ or „universal“ expressions, such as happiness or sadness. The important communicative aspect of facial expressions, however, has so far been largely neglected. Furthermore, the processing of facial expressions is influenced by dynamic information (e. g. Fox et al., 2009). However, almost all studies so far have used static expressions and thus were studying facial expressions in an ecologically less valid context (O’Toole et al., 2004). In order to enable a deeper understanding of facial expression processing it therefore seems crucial to investigate the emotional and communicative aspects of facial expressions in a dynamic context. For these investigations it is essential to first construct a database that contains such material using a well-controlled setup. In this talk, we will present the novel MPI facial expression database, which to our knowledge is the most extensive database of this kind up to date. Furthermore, we will briefly present psychophysical experiments with which we investigated the validity of our database, as well as the recognizability of a large set of facial expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.neuroschool-tuebingen-nena.de/ Ellwangen, Germany 10th Conference of Junior Neuroscientists of Tübingen (NeNa 2009) kascotKKaulard walliCWallraven dwcDWCunningham hhbHHBülthoff article 5824 IEEE Transactions on Haptics 2009 10 200 4 236-240 We report four psychophysical experiments investigating cross-modal transfer in visual and haptic face recognition. We found surprisingly good haptic performance and cross-modal transfer for both modalities. Interestingly, transfer was asymmetric depending on which modality was learned first. These findings are discussed in relation to haptic object processing and face processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www2.computer.org/portal/web/csdl/doi/10.1109/TOH.2009.18 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1109/TOH.2009.18 ldopjansLDopjans walliCWallraven hhbHHBülthoff poster 6291 2009 10 39 380.15 Animals (including humans) have to identify living moving things in the environment: these could be prey, enemies or mates and interactions with them should be actively controlled. Living things could be detected visually through their shape or their motion, or both. When shape is hard to see (fog, twilight, great distance, small animal), motion becomes an important cue. Biological motion has been studied widely using point-light displays, but these displays appear to contain some sort of shape or form information that influences recognition. To study the neural correlates of the detection of living entities from motion alone, we developed a stimulus consisting of a single moving dot, thus eliminating all possible sources of information about form, spatial arrangement, shape or structure of the object. Our single dot moved such that it appeared either self-propelled (modelled on the movements of a fly) or moved by an external force (modelled on a leaf drifting in the wind). Both types of movement were built using the same equation but differed in speed and acceleration profiles according to a small set of parameters. Low-level stimulus characteristics of the stimuli (range of positions on the screen, average speed, overall aspect of the trajectory) were kept as constant as possible. The parameters could be varied in a continuous fashion to create morphs between the self-propelled and externally-moved extremes. Consistent with expectations, behavioral experiments showed that self-propelled stimuli were perceived as more animate (= more likely to be alive) than the externally-moved stimuli, with a gradual transition occurring in the intermediary morphs. The extreme stimuli and four intermediary morphs were presented in an fMRI experiment to participants who had to categorize the stimuli into alive and non-alive. Using separate functional localizers, we located areas hMT+/V5 and the superior temporal sulcus region responding to point-light walkers, and found that neither region showed changes in BOLD response following the changes in percept. However, BOLD response in a region of the left posterior superior parietal cortex scaled with the degree of perceived animacy. This suggests that the STS is not simply a detector of all kinds of animate motion, but might only be implicated when some sort of shape information in the stimuli (as with point-light displays or with interacting dots) is contributing to the percept of animacy. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=f5dec3fb-2bb6-482d-8553-db756136f1a1&cKey=e2a39a05-441a-496b-8048-e8c4ae6e6a46 Biologische Kybernetik Max-Planck-Gesellschaft Chicago, IL, USA 39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009) en johannesJSchultz hhbHHBülthoff inproceedings 6101 Human-Computer Interaction: INTERACT 2009 2009 8 9-12 Previous studies have argued for the use of gaze-assisted pointing techniques (MAGIC) in improving human-computer interaction. Here, we present experimental findings that were drawn from human performance of two tasks on a wall-sized display. Our results show that a crude adoption of MAGIC across a range of complex tasks does not increase pointing performance. More importantly, a detailed analysis of user behavior revealed several issues that were previously ignored (such as, interference of corrective saccades, increased decision time due to variability of precision, errors due to eye-hand asynchrony, and interference with search behavior) which should influence the development of gaze-assisted technology. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.interact2009.org/ Gross, T. , J. Gulliksen, P. Kotze, L. Oestreicher, P. Palanque, R. Oliveira Prates, M. Winckler Springer

Berlin, Germany

Human-Computer Interaction: INTERACT 2009 Biologische Kybernetik Max-Planck-Gesellschaft Uppsala, Sweden 12th IFIP TC13 International Conference on Human-Computer Interaction en 978-3-642-03658-3 10.1007/978-3-642-03658-3_3 biegH-JBieg chuangLLChuang HReiterer poster SchultzL2009 Perception 2009 8 38 ECVP Abstract Supplement 137 A lot is known about the neural basis of directing attention based on explicit cues. In real life however, attention shifts are rarely directed by explicit cues but rather generated implicitly, for example on the basis of previous experience. Here, we aimed at studying attention shifts dependent on recent trial history. We asked observers to detect targets in a stream of visual stimuli with three feature dimensions: colour, shape and motion. Critically, target occurrence probability was always higher in one stimulus dimension than in the others, and probabilities switched between dimensions over blocks of trials. After each probability switch, target detection times decreased exponentially for high-probability targets and increased for low-probability targets, compatible with gradual shifts in attention dependent on trial history since the switch. BOLD signal in left prefrontal and intraparietal sulcus regions was higher in the early phase after the switch, while anterior cingulate, cuneus, precuneus, temporal and more anterior frontal regions showed more activation later after the switch. These findings are compatible with expectation about engagement of regions involved in the establishment and maintenance of attentional sets. BOLD signal in left intraparietal sulcus correlated with the size of the performance changes consecutive to the detected targets, suggesting that it reflects the size of attention shifts induced by updating target probabilities over recent trial history. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v090332 Regensburg, Germany 32nd European Conference on Visual Perception johannesJSchultz lennertTLennert poster 5954 Perception 2009 8 38 ECVP Abstract Supplement 83 Investigations of facial expressions have focused almost exclusively on the six so-called universal expressions. During everyday interaction, however, a much larger set of facial expressions is used for communication. To examine this mostly unexplored space, we developed a large video database for emotional and conversational expressions: native German participants performed 58 expressions based on pre-defined context scenarios. Three experiments were performed to investigate the validity of the scenarios and the recognizability of the expressions. In Experiment 1, ten participants were asked to freely name the facial expressions that would be elicited given the scenarios. The scenarios were effective: 82% of the answers matched the intended expressions. In Experiment 2, ten participants had to identify 55 expression videos of ten actors, presented successively. We found that 20 expressions could be identified reliably without any context. Finally, in Experiment 3, twenty participants had to group the 55 expression videos based on similarity while allowing for repeated comparisons. Out of the 55 expressions, 45 formed a consistent group, respectively, showing that visual comparison facilitates the recognition of conversational expressions. Interestingly, none of the experiments found any advantage for the universal expressions, demonstrating the robustness with which we interpret conversational facial expressions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v090219 Biologische Kybernetik Max-Planck-Gesellschaft Regensburg, Germany 32nd European Conference on Visual Perception en kascotKKaulard walliCWallraven dwcDWCunningham hhbHHBülthoff poster 5867 Perception 2009 8 38 ECVP Abstract Supplement 166 Natural gaze behavior is often studied under conditions that restrain head movements. Here, we report how the availability of head movement can influence gaze behavior on wall-sized images of natural outdoor scenes (field-of- view: ~90°). Participants performed half of the experiment with complete head mobility and the remaining trials with their heads restrained in a chin-rest. They were required to either rate the images for attractiveness (i.e., free-viewing) or to count the visible animals (i.e., visual search). On average, more fixations were found on the trials that allowed for head movements (unrestrained: 4.21 fixations/sec; restrained: 3.75 fixations/sec), which were also shorter in their mean duration (unrestrained: 221 ms; restrained: 252 ms). In addition, unrestrained gaze contained a larger proportion of small amplitude saccades (i.e., less than 5°), than head-restrained gaze. Finally, our participants demonstrated a general preference in fixating regions that were close to the central eye-in-h ead orientation. Altogether, these findings suggest that the availability of head movements allowed our participants to re-orient to regions of interest and sample these regions more frequently. This sampling benefit applied to both visual search and free viewing tasks. The current findings emphasize the importance of allowing head mobility when studying natural gaze behavior. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v090902 Biologische Kybernetik Max-Planck-Gesellschaft Regensburg, Germany 32nd European Conference on Visual Perception en chuangLLChuang sherholzSHerholz hhbHHBülthoff rolandRFleming poster 6082 Perception 2009 8 38 ECVP Abstract Supplement 172 Human-machine interfaces can be enhanced by incorporating knowledge of the user's current point of regard. For example, Zhai and colleagues (1999) showed that faster task completion times could be achieved on a simple pointing task if the display pointer was translocated according to the user's gaze. This manipulation removes the need to manually move the pointer and hence, promises time-savings that grows in proportion to display size. Here, we report the findings of applying the same technique on a wall-sized display (2.2 m × 1.8 m), across more complex pointing task. Two main components comprised the four tasks that participants were required to perform, with and without gaze-assisted pointing: Namely, conjunctive search of colored shapes and click-and-drag of items to a circumscribed region. Contrary to previous findings, we found that gaze-assisted pointer placement significantly increased task completion times, relative to manual pointer placement. Detailed analyses revealed that task complexity and individual differences in gaze behaviour and eye-hand coordination had an adverse effect on task performance, which emphasizes the importance of considering these factors in future implementations of gaze-assisted interfaces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v090846 Biologische Kybernetik Max-Planck-Gesellschaft Regensburg, Germany 32nd European Conference on Visual Perception en biegH-JBieg chuangLLChuang HReiterer poster 5918 Perception 2009 8 38 ECVP Abstract Supplement 100 In previous experiments, we showed an advantage for visual over haptic face recognition. Promoting serial encoding in vision using a novel gaze-restricted display, we found that these differences are due to modality-specific encoding strategies (holistic in vision vs serial in haptics), and that serial encoding leads to featural (vs holistic) processing. Here, we test how the observed encoding and processing differences might be affected by expertise. Participants were trained on five consecutive days on a set of 19 faces using an old/new recognition task for which three faces were learned with feedback, followed by four test-blocks. On days 1 (pre-test), 4 (post-test), and 5, the task consisted of two upright and two inverted test-blocks. On day 5, we tested participants on a different set of faces. Performance for upright faces was low on day 1, but improved significantly through training ( d1'=1.11, d4'=3.75). Importantly, this learning effect generalized to a new face-set on day 5 ( d5'=3.07). Although performance significantly improved through training, we found no inversion effect on any day ( d1'=1.70, d4'=3.54) indicating no change in processing strategies. Our results show that participants can develop efficient, generalizing strategies to compensate for encoding differences, and that these strategies do not require holistic encoding. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v090145 Biologische Kybernetik Max-Planck-Gesellschaft Regensburg, Germany 32nd European Conference on Visual Perception en ldopjansLDopjans walliCWallraven hhbHHBülthoff poster Bulthoff2009 Perception 2009 8 38 ECVP Abstract Supplement 78 According to Bruce and Young's (1986 British Journal of Psychology 77 305 - 327) classic model of face recognition, sex-related information about a face is accessed independently of information about identity. Therefore familiarity with a face should not influence sex categorization. This issue of independence has remained controversial as it has been supported in some studies and questioned in others. Here we used faces that were presented in two conditions: sex-unchanged and sex-changed. Participants were very familiar with some of the identities. For all participants, the unchanged familiar faces presented congruent identity and sex information while the sex-changed familiar faces presented incongruent identity and sex information. Participants performed a sex categorization task on all familiar and unfamiliar faces presented in the unchanged and sex-changed condition. They were asked to ignore identity and base their responses solely on the sex appearance of the faces. Our results show that participants were slower and less correct for sex-changed than for unchanged familiar faces while those differences did not appear for unfamiliar faces. These results indicate that sex and identity are not independent as participants could not ignore identity information while doing a sex categorization task. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v090132 Regensburg, Germany 32nd European Conference on Visual Perception isaIBülthoff conference 5953 Perception 2009 8 38 ECVP Abstract Supplement 159 Humans combine visual and haptic shape information in object processing. To investigate commonalities and differences of these two modalities for object categorization, we performed similarity ratings and three different categorization tasks visually and haptically and compared them using multidimensional scaling techniques. As stimuli we used a 3-D object space, of 21 complex parametrically-defined shell-like objects. For haptic experiments, 3-D plastic models were freely explored by blindfolded participants with both hands. For visual experiments, 2-D images of the objects were used. In the first task, we gathered pair-wise similarity ratings for all objects. In the second, unsupervised task, participants freely categorized the objects. In the third, semi-supervised task, participants had to form exactly three groups. In the fourth, supervised task, participants learned three prototype objects and had to assign all other objects accordingly. For all tasks we found that within-category distances were smaller than across-category distances. Categories form clusters in perceptual space with increasing density from unsupervised to supervised categorization. In addition, the unconstrained similarity ratings predict the categorization behavior of the unsupervised categorization task best. Importantly, we found no differences between the modalities in any task showing that the processes underlying categorization are highly similar in vision and haptics. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v090174 Biologische Kybernetik Max-Planck-Gesellschaft Regensburg, Germany 32nd European Conference on Visual Perception en ninagaissertNGaissert walliCWallraven hhbHHBülthoff article 4689 Attention, Perception and Psychophysics 2009 7 71 5 1107-1126 Knowing where people look on a face provides an objective insight into the information entering the visual system and into cognitive processes involved in face perception. In the present study, we recorded eye movements of human participants while they compared two faces presented simultaneously. Observers‘ viewing behavior and performance was examined in two tasks of parametrically varying difficulty, using two types of face stimuli (sex morphs and identity morphs). The frequency, duration, and temporal sequence of fixations on previously defined areas of interest in the faces were analyzed. As was expected, viewing behavior and performance varied with difficulty. Interestingly, observers compared predominantly the inner halves of the face stimuli—a result inconsistent with the general left-hemiface bias reported for single faces. Furthermore, fixation patterns and performance differed between tasks, independently of stimulus type. Moreover, we found differences in male and female participants‘ viewing behaviors, but only when the sex of the face stimuli was task relevant. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://app.psychonomic-journals.org/content/71/5/1107.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft en 10.3758/APP.71.5.1107 armannRArmann isaIBülthoff poster 5943 2009 7 10 679 172-173 Categorization studies have primarily focused on the visual percept of objects. But in every-day life humans combine percepts from different modalities. To better understand this cue combination and to learn more about the mechanisms underlying categorization, we performed different categorization tasks visually and haptically and compared the two modalities. All experiments used the same set of complex, parametrically-defined, shell-like objects based on three shape parameters (see figure and [Gaissert, N., C. Wallraven and H. H. Bülthoff: Analyzing perceptual representations of complex, parametrically-defined shapes using MDS. Eurohaptics 2008, 265-274]). For the visual task, we used printed pictures of the objects, whereas for the haptic experiments, 3D plastic models were generated using a 3D printer and explored by blindfolded participants using both hands. Three different categorization tasks were performed in which all objects were presented to participants simultaneously. In an unsupervised task participants had to categorize the objects in as many groups as they liked to. In a semi-supervised task participants had to form exactly three groups. In a supervised task participants received three prototype objects (see figure) and had to sort all other objects into three categories defined by the prototypes. The categorization was repeated until the same groups were formed twice in a row. The amount of repetitions needed across modalities was the same, showing that the task was equally hard visually and haptically. For more detailed analyses we generated similarity matrices based on which stimulus was paired with which other stimulus. As a measure of consistency – within and across modalities as well as within and across tasks – we calculated cross correlations between these matrices (see figure). Correlations within modalities were always higher than across modalities. In addition, as expected, the more constrained the task, the more consistently participants grouped the stimuli. Critically, multi-dimensional scaling analysis of the similarity matrices showed that all three shape parameters were perceived visually and haptically in all categorization tasks, but that the weighting of the parameters was dependent on the modality. In line with our previous results, this demonstrates the remarkable robustness of visual and haptic processing of complex shapes. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://imrf.mcmaster.ca/IMRF/ocs/index.php/meetings/2009/paper/view/679 Biologische Kybernetik Max-Planck-Gesellschaft New York, NY, USA 10th International Multisensory Research Forum (IMRF 2009) en ninagaissertNGaissert walliCWallraven isaIBülthoff poster 5917 2009 7 10 547 81 In previous experiments, we provided further evidence that the haptic and visual systems both have the capacity to process faces, and that face information can be shared across sensory modalities [1]. Interestingly, we found this information transfer across modalities to be asymmetric and limited by haptic face processing. Visual face perception relies on specific processes that evolve with perceptual expertise, while we have little to no training in haptic face recognition throughout life. We, therefore, suggest that the observed asymmetry in visual and haptic face processing might be attributed to different levels of expertise. To test the importance of visual experience with faces also for haptic recognition we studied haptic face recognition in the early-blind (N=10), late-blind (N=9) and sighted (N=18). Participants performed an old/new recognition task for which sets of three faces were learned haptically, followed by three subsequent haptic test-blocks. We found that early-blind participants could recognize faces haptically, although recognition accuracy was low (d’= 0.83). More interestingly, however, recognition accuracy was significantly better in late-blind (d’=1.56) as well as sighted (d’=1.42) participants. Our results, therefore, suggest that behavioral benefits in haptic face recognition require visual experience with faces. A lack thereof cannot be compensated for by purely perceptual haptic expertise as the results for the early-blind show. These findings suggest that haptic face recognition can recruit specific visual processing mechanisms that are shaped by visual experience [2]. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://imrf.mcmaster.ca/IMRF/ocs/index.php/meetings/2009/paper/view/547 Biologische Kybernetik Max-Planck-Gesellschaft New York, NY, USA 10th International Multisensory Research Forum (IMRF 2009) en ldopjansLDopjans walliCWallraven hhbHHBülthoff article 5679 NeuroImage 2009 5 45 4 1314-1328 A lot is known about the neural basis of directing attention based on explicit cues. In real life however, attention shifts are rarely directed by explicit cues but rather generated implicitly, for example on the basis of previous experience with a given situation. Here, we aimed at studying attention shifts dependent on recent trial history. While explicitly cued attention shifts involve activity in cortex of the intraparietal sulcus, whether this region is also involved in shifting attention according to recent history is still unknown. We asked observers to detect targets in a stream of visual stimuli with three feature dimensions: Color, shape and motion. Critically, target occurrence probability was always higher in one stimulus dimension than in the others, and probabilities switched between dimensions over blocks of trials. After each probability switch, target detection times decreased exponentially for high-probability targets and increased for low-probability targets, compatible with gradual shifts in attention dependent on trial history since the switch. BOLD signal in left prefrontal and intraparietal sulcus regions was higher in the early phase after the switch, while anterior cingulate, cuneus, precuneus, temporal and more anterior frontal regions showed more activation later after the switch. These findings are compatible with the engagement of regions involved in the establishment and maintenance of attentional sets. BOLD signal in left intraparietal sulcus correlated with the size of the performance changes consecutive to the detected targets, suggesting that it reflects the size of attention shifts induced by updating target probabilities over recent trial history. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/SchultzLennert_Stream_accepted_withFigs_formatted_5679[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.neuroimage.2009.01.012 johannesJSchultz lennertTLennert article 5678 Experimental Brain Research 2009 4 194 3 465-475 The ability to perceive facial motion is important to successfully interact in social environments. Previously, imaging studies have investigated neural correlates of facial motion primarily using abstract motion stimuli. Here, we studied how the brain processes natural non-rigid facial motion in direct comparison to static stimuli and matched phase-scrambled controls. As predicted from previous studies, dynamic faces elicit higher responses than static faces in lateral temporal areas corresponding to hMT+/V5 and STS. Interestingly, analyses of individually-defined, static-face-sensitive regions in bilateral fusiform gyrus and left inferior occipital gyrus also respond more to dynamic than static faces. These results suggest integration of form and motion information during the processing of dynamic faces even in ventral temporal and inferior lateral occipital areas. In addition, our results show that dynamic stimuli are a robust tool to localize areas related to the processing of static and dynamic face info rmation. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/SchultzPilz_facelocaliser_acceptedWithFigs_5678[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.springerlink.com/content/2l46216834155751/ Biologische Kybernetik Max-Planck-Gesellschaft en 10.1007/s00221-009-1721-9 johannesJSchultz kpilzKSPilz conference 5700 2009 1 Im Kontakt mit dem Kunden nimmt Kommunikation die wichtigste Rolle ein. Dabei beträgt der Anteil der nonverbalen Kommunikation erstaunliche 90%. Gesichtsausdrücke sind eine Art der Möglichkeiten, wie beide - Ihr Kunde und Sie - miteinander kommunizieren. Über diese Kommunikationsform ist bisher nur wenig bekannt: Wie interpretieren wir Gesichter? Worauf müssen wir achten? Im Rahmen dieses Vortrags sollen Erkenntnisse der Forschung im Bereich der visuellen Verarbeitung von Gesichtsausdrücken vorgestellt werden, die für die nonverbale Kommunikation essentiell sind. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.opti-munich.com/?lang=de Biologische Kybernetik Max-Planck-Gesellschaft München, Germany International Trade Fair for Trends in Optics (OPTI 2009) en kascotKKaulard walliCWallraven inproceedings 5470 Vision, Modeling and Visualization 2008: Proceedings (VMV 2008) 2008 10 101-110 We present a mobile system for tracking the gaze of an observer in real-time as they move around freely and interact with a wall-sized display. The system combines a head-mounted eye tracker with a mo- tion capture system for tracking markers attached to the eye tracker. Our open-source software library libGaze provides routines for calibrating the sys- tem and computing the viewer’s position and gaze direction in real-time. The modular architecture of our system supports simple replacement of each of the main components with alternative technology. We use the system to perform a psychophysical user-study, designed to measure how users visually explore large displays. We find that observers use head move- ments during gaze shifts, even when these are well within the range that can be com- fortably reached by eye movements alone. This suggests that free movement is important in nor- mal gaze behaviour,motivating further applications in which the tracked user is free to move. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/VMV-2008-Herholz.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.inf.uni-konstanz.de/vmv/ Deussen, O. , D. Keim IOS Press

Amsterdam, Netherlands

Biologische Kybernetik Max-Planck-Gesellschaft Konstanz, Germany 13th International Fall Workshop on Vision, Modeling, and Visualization (VMV 2008) en sherholzSHerholz chuangLLChuang tannerTGTanner hhbHHBülthoff rolandRWFleming poster GaissertWB2008 2008 10 9 6 To investigate multi-sensory, perceptual representations of three-dimensional object spaces, we generated complex, shell-shaped objects by altering three parameters defining shell shape. For haptic experiments, 3D-printed plastic models were freely explored by blindfolded participants with both hands. For visual experiments, we used 2D images of these objects. Previously, we reported results of a similarity rating task in which we split the three-dimensional object space into three orthogonal planes. Multidimensional scaling (MDS) of the pair-wise similarity ratings showed that participants reproduced the three planes almost exactly both visually and haptically. Here, we report results of a categorization task in which all objects were presented simultaneously either visually or haptically to ten participants who then categorized the objects in as many groups as they liked to. MDS analyses revealed a three-dimensional perceptual space underlying both visual and haptic data. Interestingly, the three dimensions corresponded to the parameters of shell shape with a different weighting of the dimensions in the visual and the haptic condition. Our results show that humans are able to reproduce the underlying parameters of a complex, three-dimensional object space in a similarity and categorization task using either visual or haptic modalities surprisingly well. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Ellwangen, Germany 9th Conference of the Junior Neuroscientists of Tübingen (NeNa 2008) ninagaissertNGaissert walliCWallraven hhbHHBülthoff conference ArmannB2008 2008 10 9 13 The cognitive process of categorizing perceptually similar stimuli into qualitatively different categories is fundamental to any systematic acting upon the world, as it helps to reduce the immense number of entities to more manageable fragments and spares us from learning anew each time we encounter an unknown individual. Categories are evident in all sensory modalities and range from relatively simple (e. g., color perception) to the most abstract human concepts, as for example faces. Categorical perception (CP) has been shown for face identity (e. g., Beale & Keil 1995), ethnicity (Levin & Beale, 2000), and facial expression (Calder et al., 1996). Astonishingly, for sex, a natural facial characteristic consisting of only two biologically relevant categories, con icting results have been reported so far. CP for sex has been shown (Campanella et al., 2001) when sex information was varied linearly (by morphing) between male and female face identities, thus intermixing identity and sex information. When sex continua were created based on single face identities (Bultho and Newell, 2004), no CP for sex was found in nave participants. So the question remained open whether or not there is CP for the perception of sex as a facial dimension or if processing of the sex of a face is directly linked to processing of the face's identity, as proposed by the "`single-route hypothesis"' (e. g., by Rossion, 2002, Ganel & Goshen{Gottstein, 2002; Bultho & Newell, 2004). To overcome one potential constraint of earlier studies, i. e., 'asymmetric' sex morph continua, we performed extensive ratings of faces and sex morphs from our face database, to create 'controlled' male and female faces with similar perceived degrees of 'maleness' and 'femaleness'. We then examined CP of sex for these faces with classical discrimination and classication experiments. Critically, we manipulated the degree of familiarization of the faces prior to testing, as follows. Observers were either nave, or familiarized with the average male and female face of all faces, or the endpoint identities of the morph continua, or with other male and female faces with the same perceived degree of maleness and femaleness than the test faces. Our results conrm the lack of naturally occurring CP for sex and provide more evidence for the linked processing of sex and identity, as participants showed clear CP only after familiarization with the test face identities. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Ellwangen, Germany 9th Conference of the Junior Neuroscientists of Tübingen (NeNa 2008) armannRArmann isaIBülthoff poster 5215 Perception 2008 8 37 ECVP Abstract Supplement 5 In previous experiments, we provided further evidence that 3-D face stimuli can be learnt and recognized across haptic and visual modalities. Our results suggested information transfer across modalities to be asymmetric due to differences in visual versus haptic face processing (ie, configural vs featural). To test this hypothesis, we designed two experiments investigating a visual, haptic and cross-modal face-inversion effect: Experiment 1 used an old/new recognition task in which three upright faces were learnt visually followed by three visual test-blocks (one with upright and two with inverted faces) and one haptic test-block with inverted faces. We found a strong inversion effect for visually learnt faces (visual-upright: d'=2.07, visual-inverted: d'=0.6, haptic-inverted: d'=0.52). When we exchanged learning and testing modalities in Experiment 2 (haptic learning of upright faces followed by one haptic-upright, two haptic-inverted and one visual-inverted test-blocks), we failed to find an inversion effect for haptically learnt faces (haptic-upright: d'=1.45, haptic-inverted: d'=1.75, visual-inverted: d'=1.16). Whereas visual face processing thus operates configurally, haptic processing seems to rely on featural information. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v080017 Biologische Kybernetik Max-Planck-Gesellschaft Utrecht, Netherlands 31st European Conference on Visual Perception en ldopjansLDopjans walliCWallraven hhbHHBülthoff poster 5693 Perception 2008 8 37 ECVP Abstract Supplement 117 Categorical perception (CP) has been demonstrated for face identity and facial expression, while conflicting results have been reported for sex. Furthermore, the question whether processing of sex and identity information is linked remains open. Based on extensive ratings of faces and sex morphs from our face database, we created 'controlled' male and female faces with similar perceived degrees of 'maleness' and 'femaleness'. We then examined CP of sex for these faces with classical discrimination and classification tasks using sex continua. Participants were naive (1), or had been familiarized with average faces of both sexes (2), or with the 'controlled' male and female faces (3). Our results confirm the lack of naturally occurring CP for sex in (1). Furthermore, they provide more evidence for the linked processing of sex and identity, as only participants in (3) showed clear CP. We found no evidence that familiarization with sex information (as given by average male and female faces) transfers to individual faces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v080419 Biologische Kybernetik Max-Planck-Gesellschaft Utrecht, Netherlands 31st European Conference on Visual Perception en armannRArmann isaIBülthoff poster 5680 Perception 2008 8 37 ECVP Abstract Supplement 154 Humans attribute animacy even to very simple objects displaying self-propelled or goal-directed motion. To test attribution of animacy parametrically using classical psychophysical techniques, we created animations consisting of a single dot that appeared either self-propelled (modelled on the movements of a fly) or moved by an external force (modelled on a leaf drifting in the wind). Both animations were built using the same movement equation and differed in speed and acceleration profiles, allowing parametric morphing from one ‘extreme‘ animation to the other. Low-level stimulus properties (range of screen positions covered, speed or acceleration) did not vary systematically during morphing. 26 naive subjects were asked to rate the ‘extreme‘ animations and 4 intermediate morphs for animacy. Ratings from 19 subjects as well as averages over all subjects could be modelled by a cumulative Gaussian, median PSE was in the middle of the morph range and the median JND was 1.7. These stimuli thus allow parametric testing of animacy perception from single objects with movements modelled on real animate entities. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/jschultzECVP2008_v2_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v080554 Biologische Kybernetik Max-Planck-Gesellschaft Utrecht, Netherlands 31st European Conference on Visual Perception en johannesJSchultz ldopjansLDopjans conference 5471 Perception 2008 8 37 ECVP Abstract Supplement 125 In this study we combined two new techniques to investigate visual and haptic perceptual representations of three-dimensional, parametrically-defined shapes. We generated a 3-D object space of shell-shaped objects by altering three model parameters defining shell shape. We created 21 equidistant plastic models of the objects with a 3-D printing device. Haptic exploration was done by having blindfolded participants explore these objects with both hands and no restrictions to the exploratory procedure. To ensure visual interaction without any haptic information, visual representation of these objects were presented to participants via a head-mounted display. Participants manipulated a position-tracked physical substitute to rotate the objects on the display. Pairwise similarity ratings were performed and analysed using multidimensional scaling techniques. Both visual and haptic perceptual representations were highly consistent with the underlying physical three-dimensional parameter space. Interestingly, haptic exploration resulted in a more precise perceptual representation than the visual condition. Additionally, very similar MDS maps of the visual and the haptic exploration provide evidence that one shared perceptual space is underlying both modalities. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v080449 Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics Utrecht, Netherlands 31st European Conference on Visual Perception en ninagaissertNGaissert walliCWallraven isaIBülthoff poster 5472 2008 7 9 233 192 To investigate multi-sensory, perceptual representations of three-dimensional object spaces, we generated complex, shell-shaped objects by altering three parameters defining shell shape. For haptic experiments, 3D-printed plastic models were freely explored by blindfolded participants with both hands. For visual experiments, we used 2D images of these objects. Previously, we reported results of a similarity rating task in which we split the three-dimensional object space into three orthogonal planes. Multidimensional scaling (MDS) of the pair-wise similarity ratings showed that participants reproduced the three planes almost exactly both visually and haptically. Here, we report results of a categorization task in which all objects were presented simultaneously either visually or haptically to ten participants who then categorized the objects in as many groups as they liked to. MDS analyses revealed a three-dimensional perceptual space underlying both visual and haptic data. Interestingly, the three dimensions corresponded to the parameters of shell shape with a different weighting of the dimensions in the visual and the haptic condition. Our results show that humans are able to reproduce the underlying parameters of a complex, three-dimensional object space in a similarity and categorization task using either visual or haptic modalities surprisingly well. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://imrf.mcmaster.ca/IMRF/ocs/index.php/meetings/2008/ Biologische Kybernetik Max-Planck-Gesellschaft Hamburg, Germany 9th International Multisensory Research Forum (IMRF 2008) en ninagaissertNGaissert walliCWallraven hhbHHBülthoff poster 5214 2008 7 9 214 190 In previous experiments, we provided further evidence that 3-D face stimuli can be learned and recognized by touch alone. Performance was significantly improved when haptic memory was refreshed during the experiment, indicating high memory demands due to the serial encoding process of haptic exploration. We also found that performance in a complementary visual experiment was better than in the haptic one. We suggested that these results arise from differences in encoding procedures (holistic in vision vs. serial in haptics). To test this hypothesis we designed the following two experiments which promoted serial encoding also in vision: Experiment 1 used the same old/new recognition task for which three faces were learned with three subsequent test-blocks. Participants used a mouse to move a Gaussian window which uncovered 2° of a photograph of the 3-D face. Recognition accuracy was low(d'=.98), equivalent to non-refreshed haptic performance, and significantly lower than for unrestricted visual recognition(d’=2.12). Using the same design in Experiment 2, memory was refreshed by repeated exposure to the learned faces. Performance increased significantly(d'=1.64) to levels of memory-refreshed haptic performance and unrestricted visual recognition. The performance differences in visual and haptic face recognition therefore might be attributed to modality-specific encoding strategies and memory demands. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://imrf.mcmaster.ca/IMRF/2008/pdf/FullProgramIMRF08.pdf Biologische Kybernetik Max-Planck-Gesellschaft Hamburg, Germany 9th International Multisensory Research Forum (IMRF 2008) en ldopjansLDopjans walliCWallraven hhbHHBülthoff article 4686 Cerebral Cortex 2008 6 18 6 1302-1313 Shape perception is important for object recognition. However, behavioural studies have shown that rigid motion also contributes directly to the recognition process, in addition to providing visual cues to shape. Using psychophysics and functional brain imaging, we investigated the neural mechanisms involved in shape and motion processing for dynamic object recognition. Observers discriminated between pairs of rotating novel objects in which the three-dimensional shape difference between the pair was systematically varied in metric steps. In addition, the objects rotated in either the same or different direction to determine the effect of task-irrelevant motion on behaviour and neural activity. We found that observers’ shape discrimination performance increased systematically with shape differences, as did the haemodynamic responses of occipito-temporal, parietal and frontal regions. Furthermore, responses in occipital regions were only correlated with observers’ perceived shape differences. We also found d ifferent effects of object motion on shape discrimination across observers which were reflected in responses of the superior temporal sulcus. These results suggest a network of regions that are involved in the discrimination of metric shape differences for dynamic object recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://cercor.oxfordjournals.org/content/18/6/1302.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft en 10.1093/cercor/bhm162 johannesJSchultz chuangLChuang qvuongQCVuong inproceedings 5162 Haptics: Perception, Devices and Scenarios (Eurohaptics 2008) 2008 6 265-274 In this study we show that humans are able to form a perceptual space from a complex, three-dimensional shape space that is highly congruent to the physical object space no matter if the participants explore the objects visually or haptically. The physical object space consists of complex, shell-shaped objects which were generated by varying three shape parameters. In several psychophysical experiments participants explored the objects either visually or haptically and performed similarity ratings. Multidimensional scaling (MDS) analyses showed high congruency of the visual and haptic perceptual space to the physical object space. Additionally, visual and haptic exploration resulted in very similar MDS maps providing evidence for one shared perceptual space underlying both modalities. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Eurohaptics2008-Gaissert_5162[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.disam.upm.es/~eurohaptics2008/ Ferre, M. Springer

Berlin, Germany

Haptics: Perception, Devices and Scenarios Biologische Kybernetik Max-Planck-Gesellschaft Madrid, Spain 6th International Conference EuroHaptics 2008 en 978-3-540-69056-6 10.1007/978-3-540-69057-3_31 ninagaissertNGaissert walliCWallraven hhbHHBülthoff thesis 5699 2008 2 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Hochschule Aalen, Germany Diplom en kascotKKaulard article 4870 Spatial Vision 2007 12 21 1 165-184 When observing art the viewer’s understanding results from the interplay between the marks made on the surface by the artist and the viewer’s perception and knowledge of it. Here we use a novel set of stimuli to dissociate the influences of the marks on the surface and the viewer’s perceptual experience upon the manner in which the viewer inspects art. Our stimuli provide the opportunity to study situations in which (1) the same visual stimulus can give rise to two different perceptual experiences in the viewer, and (2) the visual stimuli differ but give rise to the same perceptual experience in the viewer. We find that oculomotor behaviour changes when the perceptual experience changes. Oculomotor behaviour also differs when the viewer’s perceptual experience is the same but the visual stimulus is different. The methodology used and insights gained from this study offer a first step toward an experimental exploration of the relative influences of the artist’s creation and viewer’s perception when viewing art and also toward a better understanding of the principles of composition in portraiture. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://springerlink.metapress.com/content/58h411820678484p/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1163/156856807782753903 BWTatler NJWade kascotKKaulard poster 4687 2007 11 37 304.4 An essential need of brain function is the detection of living entities, and one of the major characteristics for their identification is their motion. Humans are very good at recognizing living entities from their motion, and attribute animacy to even very simple objects displaying self-propelled or goal-directed motion. Our previous results (1) show that increasing correlation between the movements of two simple interacting objects leads to A) an increase in the impression of goal-directed motion and of animacy and B) to increasing BOLD signal in the superior temporal sulcus (STS), suggesting that STS is involved in decoding the information leading to the percept of animacy. This is consistent with previous studies implicating the posterior part of the STS in recognition of biological motion. In the current study, 7 volunteering patients undergoing investigations prior to epilepsy surgery observed the animate motion stimuli used in (1). Simultaneously, we recorded multichannel subdural electrocorticogram data from healthy cortex surrounding the STS and performed trial-by-trial frequency decomposition over time. We found that power in the 30-60Hz frequency band (gamma band) between 1 and 2 seconds after stimulus onset showed a significant parametric response to the amount of goal-directed motion, paralleling our previous BOLD signal findings (1). Furthermore, due to the high temporal resolution of these data, we were able to localize at which time points during the animations the strongest response in the STS occurred. Our results confirm the importance of the STS in processing of visual characteristics of animate entities, and suggest that neuronal activity in this area changes over the duration of the animations. We are currently comparing time-varying attributes of the stimuli to the time-course of gamma-band activity to reveal which events in the stimuli drive STS activity. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sfn.org/am2007/ Biologische Kybernetik Max-Planck-Gesellschaft San Diego, CA, USA 37th Annual Meeting of the Society for Neuroscience (Neuroscience 2007) en johannesJSchultz MXCohen SHaupt hhbHHBülthoff CElger poster 4715 Perception 2007 8 36 ECVP Abstract Supplement 207 Prior studies have shown that humans can recognize faces by touch alone. This study investigated haptic face recognition with two experiments using a well-defined stimulus face-space based on the morphable MPI-Face-Database. In Experiment 1, we used an old/new recognition task for which different sets of three faces (out of six) were learned haptically with three subsequent haptic test-blocks and one visual test-block. We found that participants could recognize faces haptically although recognition accuracy was low (65%) and tended to decrease across blocks. Cross-modal recognition however was at chance level (48%). In Experiment 2, haptic memory was refreshed before each test-block by repeated exposure to the three learned faces. We found that performance increased significantly to 76% and that it became more consistent across blocks. Most importantly, however, we found clear evidence for cross-modal recognition as visual performance rose above chance level (62%). Our results demonstrate that during visual face recognition, participants have access to information learned during h aptic exploration allowing them to perhaps form a visual image from haptic information. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v070525 Biologische Kybernetik Max-Planck-Gesellschaft Arezzo, Italy 30th European Conference on Visual Perception en ldopjansLDopjans walliCWallraven hhbHHBülthoff poster 5019 Perception 2007 8 36 ECVP Abstract Supplement 49 Humans learn and recognize objects through active exploration. Sixteen participants freely explored 3-D amoeboid objects in a virtual-reality environment during learning. They handled a device whose spatial coordinates determined the object‘s position relative to its viewpoint. These exploration patterns were also recorded for testing. In a subsequent old/new recognition test, participants either actively explored or passively viewed old (learned) and new objects in the same setup. Generally, active participants performed better than passive participants (in terms of sensitivity: d 0 ˆ 1:08 vs 0.84, respectively). Despite this, those participants who passively viewed objects animated with their personal motion trajectories for learned objects maintained com- parable performance to that of participants who actively explored the objects (d 0 ˆ 1:13). In contrast, passive observers‘ performance decreased when these trajectories were temporally reversed (d 0 ˆ 0:69) or when another observer‘s motion trajectories were used (d 0 ˆ 0:70). While active exploration generally allowed better recognition of objects compared to passive viewing, our observers could rely on idiosyncratic exploration patternsöin which particular aspects of object structure were revealed over timeöto achieve equivalent performance. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v070732 Biologische Kybernetik Max-Planck-Gesellschaft Arezzo, Italy 30th European Conference on Visual Perception en chuangLLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster 5021 Perception 2007 8 36 ECVP Abstract Supplement 146 Whether recognition and categorization are parallel or serial processes remains controversial. To address this, we investigated whether face recognition is influenced by task-irrelevant face categ- ories. We examined the recognition of a target face presented in the context of other faces of the same or different racial category using a same ^ different matching task. Caucasian partici- pants were presented during learning with a set of six faces displaying one target face among different numbers of same-race faces. Participants recognized Caucasian targets better when five same-race faces rather than a single same-race face were present in the set, while this effect was absent for Asian targets. Surprisingly, participants recognized Asian targets better in sets with equal numbers of Asian and Caucasian context faces. Similar experiments, but with novel objects, were conducted in which categories were defined by similarity or expertise. These factors did not fully account for the context effects observed with faces. Overall, the results suggest that face recognition and categorization interact but other factors such as task difficulty may also affect face recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v070371 Biologische Kybernetik Max-Planck-Gesellschaft Arezzo, Italy 30th European Conference on Visual Perception en isaIBülthoff qvuongQCVuong inproceedings 4463 Proceedings of the 4th Symposium on Applied Perception in Graphics and Visualization (APGV‘07) 2007 7 115-122 The question of how humans perceive art and how the sensory percept is endowed with aesthetics by the human brain has continued to fascinate psychologists and artists alike. It seems, for example, rather easy for us to classify a work of art as either "abstract" or "representational". The artist Robert Pepperell recently has produced a series of paintings that seek to defy this classification: his goal was to convey "indeterminancy" in these paintings - scenes that at first glance look like they contain an object or belong to a certain genre but that upon closer examination escape a definite determination of their contents. Here, we report results from several psychophysical experiments using these artworks as stimuli, which seek to shed light on the perceptual processing of the degree of abstraction in images. More specifically, the task in these experiments was to categorize a briefly shown image as "abstract" or "representational". Stimuli included Pepperell‘s paintings each of which was paired with a similar representational work of art from several periods and several artistic genres. The results provide insights into the visual processes determining our perception of art and can also function as a "objective" validation for the intentions of the artist. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/apgv07-115_4463[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.apgv.org/archive/apgv07/ Wallraven, C. , V. Sundstedt ACM Press

New York, NY, USA

Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 4th Symposium on Applied Perception in Graphics and Visualization (APGV 2007) en 978-1-59593-670-7 10.1145/1272582.1272605 walliCWallraven kascotKKaulard coraCKürner RPepperell hhbHHBülthoff poster 4716 2007 7 10 66 Prior studies have shown that humans can recognize faces by touch alone but perform poorly in cross-modal face recognition [1]. Here we want to shed further light on haptic face recognition with four experiments using a well-defined stimulus face space based on the morphable MPIFace- Database. Experiment 1 used a same/different task with sequentially presented faces which established that subjects were able to discriminate faces haptically, using short term memory. In Experiment 2 we used an old/new recognition task for which different sets of three faces (out of six) were learned haptically with three subsequent haptic test-blocks and one visual test-block. In contrast to Casey and Newell (2007) we used the same printed face masks for recognition in both modalities. We found that participants could recognize faces haptically although recognition accuracy was low (65%) and tended to decrease across blocks. Cross-modal recognition, however, was at chance level (48%). In Experiment 3, we changed the design such that haptic memory was refreshed before each test-block by repeated exposure to the three learned faces. We found that performance increased significantly to 76% and that it became more consistent across blocks. Most importantly, however, we found clear evidence for cross-modal transfer as visual performance rose above chance level (62%). Our results demonstrate that during visual face recognition, participants have access to information learned during haptic exploration allowing them to perhaps form a visual image from haptic information. In Experiment 4, we interchanged learning and recognition modality with respect to Experiments 2+3, testing within-modality recognition in the visual domain and cross-modal transfer by haptic recognition of the face masks. Using the same experimental design as in Experiment 2, we found that performance in the visual within-modality condition increased significantly to 89% and that it became more consistent across blocks (71% compared to 39% for Experiment 2). However, recognition accuracy decreased across blocks (from 96% to 87%). Interestingly, cross-modal performance was significantly higher than in Experiments 2 (at 69%) demonstrating a clear advantage in cross-modal transfer for vision as the learning modality. The reasons for the observed differences in cross-modal transfer remain to be investigated. Possible factors include differences in visual versus haptic memory permanence, vision as the dominant and therefore preferred learning modality, and finally the role of visual imagery in cross-modal transfer. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk07/abstract.php?_load_id=dopjans01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 10th Tübinger Wahrnehmungskonferenz (TWK 2007) en ldopjansLDopjans walliCWallraven hhbHHBülthoff poster 4882 2007 7 10 109 In the German population, men are on average 13 cm taller than women [1]. Smaller people, many of them women, look at other faces from below (viewing angle) while tall people look at others from above. The minimal distance between 2 persons not engaged in mutual gaze is around 50 cm [2]. Thus, with regard to male and female average statures, in close-up situations, the average viewing angle between males and females is around 13 deg. Do people have therefore different “preferred” representations of faces depending on their stature? More specifically, are tall and small people more efficient at processing face seen “from above” and from “below” respectively? Furthermore, do observers have different “preferred” representations of male and female faces because men are on average taller than women? To investigate the influence of stature and sex on face recognition, we first investigated whether efficiency in a sex classification task might be influenced by face orientation. To maximize stature differences between participants, we tested two groups: small women (under 165cm) and tall men (over 180cm). If face representation is influenced by stature, we expect small women to be more efficient (faster) at processing faces viewed as seen from below and vice-versa for tall men. Furthermore, because of natural average stature differences between men and women, efficient categorization of male and female faces might depend on their orientation. We used unfamiliar male and female faces shown at pitch angles between -18 deg (looking downward) to +18 deg (looking upward). We tested participants in a speeded sex classification task. Male and female participants saw 220 faces one by one and had to classify them as male or female as fast as possible. Classification accuracy was high (over 95%). Analysis of reaction times does not show any relation between stature of observer, sex of shown face and its pitch orientation, thus suggesting that face processing with regards to sex is not influenced predominantly by stature of observer or sex of presented face. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk07/abstract.php?_load_id=buelthoff01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 10th Tübinger Wahrnehmungskonferenz (TWK 2007) en isaIBülthoff towolfTWolf ianIMThornton poster 4860 2007 7 10 103 Current research shows that human object recognition is sensitive to the learned order of familiar object views (e.g. [1]). This temporal order of views could be determined by how an observer manipulates an object during learning e.g., rigid rotations in depth. In fact, the freedom to manipulate objects during learning is also known to improve subsequent recognition from single static images [2]. In this study, sixteen participants learned novel 3D amoeboid objects by manipulating them in a virtual reality environment. This required the use of a marker tracking system (VICON) and a head-mounted display (z800 3DVisor eMagin). Our participants handled a tracked device whose spatial coordinates, relative to the observers’ viewpoint, determined the position and orientation of a virtual object that was presented via the head-mounted display. Hence, this device acted as a physical substitute for the virtual object and its coordinates were recorded as motion trajectories. In a subsequent old/new recognition test, participants either actively explored or passively viewed old (learned) and new objects in the same setup. Generally, “active” participants performed better than “passive” participants (in terms of sensitivity: d’=1.08 vs. 0.84 respectively). Nonetheless, passive viewing of learned objects that were animated with their learned motion trajectories resulted in comparably good performance (d’=1.13). The performance decrease was specific to passively viewing learned objects that either had their learned motion trajectories temporally reversed (d’=0.69) or followed another observer’s motion trajectories (d’=0.70). Therefore, object recognition performance from passively viewing one’s past explorations of the learned object is comparable to actively exploring the learned object itself. These results provide further support for a dependence on temporal ordering of views during object recognition. Finally, these results could also be considered in the context of studies that highlight the human ability of discriminating one’s own actions from other people’s actions e.g., hand gestures, handwriting, dart-throwing, full-body walking and ballet (for discussion and examples, see [3]). Here, our study also showed better recognition from viewing videos of self-generated actions. Nonetheless, this recognition benefit was specifically for the learned objects, which were not concretely embodied in the observer’s person. Moreover, animating new objects with the participants’ own actions did not increase their familiarity. We conclude by suggesting that our observers’ did not merely show a familiarity with their past actions but rather, with the idiosyncratic visual experiences that their own actions created. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk07/abstract.php?_load_id=chuang01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 10th Tübinger Wahrnehmungskonferenz (TWK 2007) en chuangLLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster 4881 2007 7 10 108 Knowing where people look in a face provides an objective insight onto the information entering the visual system and into the cognitive processes involved in face perception. Eye-tracking studies on face perception have mostly investigated observers’ viewing behavior when studying single faces. However, in day-to-day situations, humans also compare faces or match a person’s face to a photograph. During comparison, facial information remains visually accessible, freeing observers from time and encoding constraints [1]. Here, we recorded eye movements of human participants while they compared two faces presented simultaneously. We used (i) two different tasks (discrimination or categorization), and (ii) faces differing either in identity or in sex. In addition, we varied (iii) task difficulty, i.e. the similarity of the two faces in a pair. Eye movements to previously defined areas of interest (AOIs) on the faces were analyzed in terms of frequency, duration and the temporal pattern of fixations made. We found that the eyes were fixated most often in the discrimination tasks (37% of all fixations) but the nose in the categorization task (34.5%), while the total number of fixations increased with task difficulty. Faces differing in sex were more difficult to discriminate than faces differing in identity (63% versus 76% correct responses), which was also reflected in more fixations to face pairs differing in sex (14.4 versus 11.8 fixations per trial). With increasing task difficulty, fixations to only some AOIs increased, in accordance with the literature (more to the eyes in the sex and more over all areas in the identity discrimination tasks; [2]). Unexpectedly, we found a striking effect of tasks on performance measures, as over 80% of participants could detect the more feminine of two faces (categorization task) even at the most similar level, but for the same face pairs their performance in a discrimination task was less than 30% correct. Another interesting finding is that observers mostly compared the inner halves of the two faces of a pair, instead of the corresponding features (e.g., the left eye of the left face with the left eye of the right face). This viewing behavior remained the same in a control experiment where participants’ head was not fixed. Quite surprisingly, female participants fixated significantly more often the eyes of the face stimuli than male participants, but only when the sex of the faces was a relevant feature in the task. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk07/abstract.php?_load_id=armann01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 10th Tübinger Wahrnehmungskonferenz (TWK 2007) en armannRArmann isaIBülthoff poster 4852 2007 7 10 49 Attention determines which aspects of the incoming sensory information are processed with priority. However, attention is seldom an all-or-none process but rather distributed over multiple kinds of incoming information, and this distribution must be updated according to events in the world. Despite its ubiquity, this dynamic updating has been little studied in psychophysics, and even less is known about its neural correlates. In order to investigate attention updating, we studied serial detection of targets in different dimensions (color, shape or motion) of visual stimuli. Performance changed according to target sequence, and could be explained by this simple behavioral model: Each detected target was followed by a discrete attention shift towards the dimension in which the target occurred, leading to a short-lasting, exponentially decaying performance benefit. Continuously changing performance over time reflected the dynamic updating of attention induced by the sequence of detected targets. BOLD signal predicted by this time-course of attention changes was found exclusively in left parietal cortex, suggesting that neural activity in this area directly reflects how world events influence the distribution of attention. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk07/abstract.php?_load_id=schultz01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 10th Tübinger Wahrnehmungskonferenz (TWK 2007) en johannesJSchultz lennertTLennert hhbHHBülthoff inproceedings 4466 Computational Aesthetics 2007: Eurographics Workshop on Computational Aesthetics in Graphics, Visualization and Imaging (CAe‘07) 2007 6 121-128 How do we interpret an object - a scene - a painting? Perception research and art illuminate from different angles how the vast amount of information in our visually perceived environment is processed by the viewer to form a coherent and consistent interpretation of the world. Using drawings and paintings by the artist Robert Pepperell, this work attempts to connect these different world views. Pepperell's paintings at first glance seem to be a baroque fresco, an expressionist still-life, or a cubist collage; taking a closer look, however, this concrete interpretation vanishes and we are left with an indeterminate painting. Using psychophysical experiments and eye tracking measures, in this work we seek to illuminate the visual processing of information in Pepperell's paintings. More specifically, we will investigate how the pattern of fixations - the loci of interest - change as a function of the task ("What is depicted in this scene?" vs. "Does this image contain people?") and of the image content. The interpretation of the experimental results in the context of perceptual research will give first insights into the perception of (indeterminate) art. Conversely, the results are also relevant for art, as they provide a kind of perceptual, measurable "validation" of the artist's intentions. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/CAe-2007-Wallraven.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.eg.org/EG/DL/WS/COMPAESTH/COMPAESTH07 Cunningham, D. W., G. W. Meyer, L. Neumann, A. Dunning, R. Paricio Eurographics Association

Aire-la-Ville, Switzerland

Computational aesthetics 2007 Biologische Kybernetik Max-Planck-Gesellschaft Banff, Alberta, Canada Eurographics Workshop on Computational Aesthetics in Graphics, Visualization and Imaging (CAe '07) en 978-3-905673-43-2 10.2312/COMPAESTH/COMPAESTH07/121-128 walliCWallraven kascotKKaulard coraCKürner RPepperell hhbHHBülthoff poster 4690 Journal of Vision 2007 6 7 9 5 Eye-tracking studies on face perception have mostly investigated observer's eye movement behavior when studying single faces. However, in day-to-day situations, humans also compare faces or try to match a person's face to a photograph. During comparison, facial information remains visually accessible. This frees observers from time and encoding constraints (Galpin & Underwood, 2005). Here, we present eye movement data of participants required to compare two faces that were presented side by side. We used (1) two different tasks (discrimination or categorization), and (2) two types of face stimuli: faces differing either in identity or in sex. In addition, we varied for (3) task difficulty i.e. the similarity of the two faces in a pair. Eye-fixations in predefined facial regions were recorded and analyzed, for example, with regards to their frequency and duration. Our findings reveal, for instance, that the eyes were fixated more often in the discrimination tasks (38% of all fixations) than in the categorization task (29%), while the total number of fixations increased significantly with increasing task difficulty (p [[lt]] 0.001 in all cases, N=20). Faces differing in sex were more difficult to discriminate than faces differing in identity (63 % versus 76 % correct responses), which was reflected by increased fixations to face pairs that differed in sex (14.4 versus 11.8 fixations per trial). Unexpectedly, we found a striking effect of tasks on performance measures, as over 80 % of participants could detect the more feminine of two faces (categorization task) even at the most similar level, but for the same face pairs their performance in a discrimination task was less than 30 % correct. Viewing behavior of male and female participants differed, but only when the sex of the faces was relevant for the task. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Poster_VSS_2007_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/7/9/5/ Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA 7th Annual Meeting of the Vision Sciences Society (VSS 2007) en 10.1167/7.9.5 armannRArmann isaIBülthoff poster 5036 Journal of Vision 2007 6 7 9 7 Both shape and surface dimensions play an important role in face (e.g. O'Toole et al., 1999) and race recognition (Hill et al., 1995). However, the relative contribution of these cues to other-race (OR) face recognition has not been investigated. Some facial properties may be diagnostic in one race but not in the other (e.g. Valentine, 1991). Observers of different races would rely on facial cues that are diagnostic for their own-race faces, a phenomenon which could partly explain our relative difficulty at recognizing OR faces at the individual level (the so-called other-race effect). Here, we tested this hypothesis by examining the relative role of shape and surface properties in the other-race effect (ORE). For this purpose, we used Asian and Caucasian faces from the MPI face database (Vetter & Blanz, 1999) so that we could vary both shape and surface information, only shape information (in which the surface texture was averaged across individual faces of the same race), or only surface information (in which shape was averaged). The ORE was measured in Asian and Caucasian participants using an old/new recognition task. When faces varied along both shape and surface dimensions, Asians and Caucasians showed a strong ORE (i.e. a better recognition performance for same- than other-race faces). With faces varying along only shape dimensions, the ORE was no longer observed in Asians, but remained present in Caucasians. Finally, when presented with faces varying only along surfacedimensions, the ORE was not found for Caucasians whereas it was present in Asians. These results suggest that the difficulty in recognizing OR faces for Asian observers can be partly due to their inability to discriminate among surface properties of OR faces, whereas ORE for Caucasian participants would be mainly due to their inability to discriminate among shape cues of OR faces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/7/9/7/ Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA 7th Annual Meeting of the Vision Sciences Society (VSS 2007) en 10.1167/7.9.7 CMichel BRossion WHayward isaIBülthoff qvuongQVuong poster 4872 Medicine and Science in Sports and Exercise 2007 5 39 5 Supplement 265 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.acsm-msse.org/pt/re/msse/toc.00005768-200705001-00000.htm;jsessionid=H0cLMJXk6FVLQq5z1J92TRbHKJW195vvzc5hNCMjsNVZsJZMpM6p!-383192544!181195628!8091!-1 Biologische Kybernetik Max-Planck-Gesellschaft en GJendrusch SJanda kascotKKaulard ABolsinger MBach BLingelbach PPlaten poster 4265 Neuroforum 2007 4 13 Supplement 1199 The representation of the nonlinear response properties of a neuron by a Wiener series expansion has enjoyed a certain popularity in the past, but its application has been limited to rather low-dimensional and weakly nonlinear systems due to the exponential growth of the number of terms that have to be estimated. A recently developed estimation method [1] utilizes the kernel techniques widely used in the machine learning community to implicitly represent the Wiener series as an element of an abstract dot product space. In contrast to the classical estimation methods for the Wiener series, the estimation complexity of the implicit representation is linear in the input dimensionality and independent of the degree of nonlinearity. From the neural system identification point of view, the proposed estimation method has several advantages: 1. Due to the linear dependence of the estimation complexity on input dimensionality, system identification can be also done for systems acting on high-dimensional inputs such as images or video sequences. 2. Compared to classical cross-correlation techniques (such as spike-triggered average or covariance estimates), similar accuracies can be achieved with a considerably smaller amount of data. 3. The new technique does not need white noise as input, but works for arbitrary classes of input signals such as, e.g., natural image patches. 4. Regularisation concepts from machine learning to identify systems with noise-contaminated output signals. We present an application of the implicit Wiener series to find the low-dimensional stimulus subspace which accounts for most of the neuron's activity. We approximate the second-order term of a full Wiener series model with a set of parallel cascades consisting of a linear receptive field and a static nonlinearity. This type of approximation is known as reduced set technique in machine learning. We compare our results on simulated and physiological datasets to existing identification techniques in terms of prediction performance and accuracy of the obtained subspaces. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Schölkopf Research Group Bethge http://www.neuro.uni-goettingen.de/nbc.php?sel=archiv Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Germany 31st Göttingen Neurobiology Conference en mofMOFranz jakobJHMacke ASaleem SRSchultz conference 4256 2006 11 7 13 In visual object recognition, it is important to understand which object properties are important for learning. Typically, this is done by comparing recognition performance across experimental conditions that manipulate and isolate different aspects of object properties e.g., distinctive features. However, such an approach requires object properties to be explicitly specified prior to testing and is, hence, limited by the experimenter’simagination (or the lack thereof). Here, I will present a different approach to studying this problem. Rather than predefine the object properties of interest, participants are free to explore all aspects of a set of novel 3D objects during learning. Raw data are collected on observers’ patterns of exploration and analyses are subsequently applied to understand which object properties are valued by the observers during learning. In my presentation, I will describe the technical apparatus that supports this experimental approach. In addition, I will provide details on how raw data are collected and the methods of post-hoc analyses that can be applied to the data. There are several advantages to this approach in addition to those already mentioned. Firstly, this approach places control in the hands of the observer. Thus, stimulus presentation is determined by the observer’s goals rather than the experimenter’s preconceptions. This results in findings that are closer to ecological validity. Also, the raw data lend itself to reanalysis when new methods of analyses are devised or when previously unconsidered object properties later prove to be relevant for object learning. The purpose of this presentation is to generate an open discussion on the merits and disadvantages of this approach to studying visual object recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Biologische Kybernetik Max-Planck-Gesellschaft Oberjoch, Germany 7th Conference of the Junior Neuroscientists of Tuebingen (NeNa 2006) en chuangLChuang inbook 3812 2006 10 315-325 Although the perception of our world is experienced as effortless, the processes that underlie object recognition in the brain are often difficult to determine. In this article we review the effects of familiarity on the recognition of moving or static objects. In particular, we concentrate on exemplar-level stimuli such as walking humans, unfamiliar objects and faces. We found that the perception of these objects can be affected by their familiarity; for example the learned view of an object or the learned dynamic pattern can influence object perception. Deviations in the viewpoint from the familiar viewpoint, or changes in the temporal pattern of the objects can result in some reduction of efficiency in the perception of the object. Furthermore, more efficient sex categorization and cross-modal matching was found for familiar than for unfamiliar faces. In sum, we find that our perceptual system is organized around familiar events and that perception is most efficient with these learned events. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Visual%20Perception_Part_1_315-325_middle_3812[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.elsevier.com/wps/find/bookdescription.cws_home/710077/description#description Martinez-Conde, S. , S. Macknick, L. Martinez, J.-M. Alonso, P. Tse Elsevier

Amsterdam, Netherlands

Progress in Brain Research ; 154A Visual Perception Part 1: Fundamentals of vision: Low and Mid-level processes in perception Biologische Kybernetik Max-Planck-Gesellschaft en 978-0-444-52966-4 10.1016/S0079-6123(06)54017-8 isaIBülthoff fionaFNNewell poster 4093 2006 10 36 567.17 Temporal patterning of stimuli can affect performance and be critical for perceptual learning. We studied the neural correlates of trial history effects using a task in which detection time was influenced by target history. Using an MRI scanner we measured BOLD signal changes while 12 subjects were presented with streams of stimuli of variable colors, shapes, and motion directions. Participants had to attend to all 3 stimulus dimensions simultaneously to report targets consisting of unpredictable stimulus feature repetitions. Response times for targets in each stimulus dimension decreased exponentially with the number of successive targets and were well explained by a leaky integrator of target history with fast exponential decay (half-life = 1.21 trials). Significant BOLD responses (random-effects analysis over 12 subjects, threshold = p<0.05 corrected for family-wise errors at the cluster level for all reported effects) predicted by theoretical neuronal activity reflecting the leaky integrator output for all stimulus dimensions were found bilaterally in the striatum (putamen, head and body of caudate). In addition, significant BOLD signal increases were observed in response to detected targets of any stimulus dimension in lateral occipital cortex and fusiform gyri bilaterally, with specific responses in regions compatible with area MT for motion targets, with area LO for shape targets and with area V4v for color targets. Our behavioural data show that detected targets induce a benefit in response time for subsequent targets in the same stimulus dimension, that this acceleration effect is short-lived and can be modelled by a leaky integrator of target history. Our fMRI data show 1) BOLD signal increases compatible with neural activity reflecting the leaky integrator signals in striatum, in line with a role of the striatum in guiding motor behaviour in response to sensory cues and 2) BOLD signal increases in extrastriate visual areas in response to detected targets, reflecting immediate sensory consequences of detected targets. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sfn.org/index.aspx?pagename=abstracts_ampublications Biologische Kybernetik Max-Planck-Gesellschaft Atlanta, GA, USA 36th Annual Meeting of the Society for Neuroscience (Neuroscience 2006) en johannesJSchultz hhbHHBülthoff poster ConradMS2006 Perception 2006 8 35 ECVP Abstract Supplement 101-102 During continuous viewing of multistable figures, such as the Necker cube, perception alternates between equally valid solutions. So how can perceptual experience be stable given that various alternative interpretations of the same physical stimulus are available? Previous demonstrations with bistable stimuli have revealed that a repetitive intermittent presentation leads to a stabilisation of the percept. Recent research findings suggested that interleaved presentation of several ambiguous stimuli does not disrupt the perceptual stabilisation of each reversible pattern, suggesting that perceptual 'memory stores' coexist independently for each representation. Interference effects were only obtained for structurally similar stimuli. In the present study, we adopted Maier et al's interleaved presentation paradigm to investigate the effects of interfering ambiguous patterns upon transition probability and the stabilisation process. Rather than manipulating structural similarities between interleaved ambiguous stimuli, we sequentially presented ambiguous figures that share equivalent reversal processes such as figure - ground segregation or perspective reversal. The results reveal that perceptual dominance time of the ambiguous test stimulus decreases compared to periods during which a blank interval is presented, indicating an effect of interference from the distractor. Interaction between reversal processes influences the stabilisation of perception that is normally observed during repetitive intermittent presentation with blank intervals. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v060434 St. Petersburg 29th European Conference on Visual Perception conradVConrad jsmJSMcDonald johannesJSchultz poster BulthoffN2006 Perception 2006 8 35 ECVP Abstract Supplement 204 We had shown that memory for a face can be influenced by the distinctiveness of an utterance to which it has been associated (Bülthoff and Newell, 2004 Perception 33 Supplement, 108). Furthermore, recognition of a face can be primed by a paired utterance, suggesting that there is a tight, cross-modal coupling between visual and auditory stimuli and that face distinctiveness can be influenced by cross-modal interaction with auditory stimuli like utterances. When instrumental sounds are used instead of utterances, the perceptual quality of auditory stimuli seemed also to affect memory for faces. Here we further investigated whether instrumental sounds can also prime face recognition. Our results show that this is not the case; arbitrary auditory stimuli do not prime recognition of faces. This suggests that utterances are easier to associate closely with faces than arbitrary sounds. We also investigated whether the observed priming effect of utterances might have been based on the use of different first names in each utterance. We repeated the priming experiment using the same utterances, but name information was removed. A significant priming effect was observed. Thus the semantic information related to the first name is not decisive for the priming effect of utterances on face recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v060143 St. Petersburg 29th European Conference on Visual Perception isaIBülthoff fionaFNNewell poster ChuangVTB2006 Perception 2006 8 35 ECVP Abstract Supplement 33 Binocular rivalry can occur when two different stimuli are presented separately to each eye. Typically, the dominant percept alternates between the two presented stimuli. Prior studies have shown that perceptual dominance can be induced by low-level factors such as luminance as well as high-level factors such as object categories, suggesting that rivalry reflects competition at multiple levels of visual processing. Here, we investigated whether learned shape and motion of rigidly rotating objects can bias perceptual dominance during binocular rivalry. Observers first learned four novel objects that each rotated in a specific direction. These objects were randomly created by free-form deformation techniques. Following learning, we induced binocular rivalry between a learned object and a novel distractor. The learned object could rotate in its learned or reversed direction. For comparison purposes, we also included pairs of only novel objects. Initial results show that learned objects rotating in their learned direction are perceptually dominant more often than the paired distractors. Learned objects rotating in reverse do not appear to differ from novel objects in terms of perceived dominance. These findings suggest that binocular rivalry could provide a useful implicit measure of the roles played by shape and motion during object recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v060355 St. Petersburg 29th European Conference on Visual Perception chuangLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster 4226 Perception 2006 8 35 ECVP Abstract Supplement 99 The role of object parts is a key issue in object recognition. Here we investigated whether observers encode qualitative (eg straight versus curved part) or metric information of parts (eg curvature magnitude), and whether the information that is encoded can be affected by motion. To address these issues, we constructed a novel set of objects composed of parts that can vary metrically along different dimensions (eg tapering and bending) to create qualitatively different parts. In a same/different matching task, we presented two objects rigidly rotating in the same or different direction, and had observers judge whether these objects were the same or different. We varied the pair of objects along an &lsquo;identity&lsquo; axis by morphing between two exemplars. A cumulative Gaussian function explained the effect of morph level, suggesting that observers encoded metric information. There was a slight shift of the psychometric function for same versus different motion. Overall, our results suggest that observers are sensitive to metric information, even for objects with salient part structure. We are currently investigating with fMRI how object parts and motion influence neuronal object processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v060406 Biologische Kybernetik Max-Planck-Gesellschaft St. Petersburg, Russia 29th European Conference on Visual Perception en qvuongQCVuong johannesJSchultz chuangLChuang conference 4092 Perception 2006 8 35 ECVP Abstract Supplement 128 Temporal patterning of stimuli can affect performance and be critical for perceptual learning. We tested whether trial history can explain target detection time even when target occurrence is unpredictable. 12 volunteers were presented with streams of stimuli of variable color, shape, and motion direction, and had to attend to all stimulus dimensions simultaneously to report Poisson-determined, 1-back repetitions in either dimension. Response times decreased exponentially with the number of successive targets (group means for 1 to 4 targets in succession: 1050, 763, 717, 722 milliseconds; 2-way repeated measures ANOVA: F(3,33) = 195, p&amp;amp;amp;lt;&amp;amp;amp;lt;0.0001, no main effect of stimulus dimension but interaction between dimension and number of successive targets: F(6,66) = 5.11, p&amp;amp;amp;lt;0.001). Response times were well explained by a leaky integrator of trial history with fast exponential decay (half-life = 1.21 trials; correlation coefficients significant at p&amp;amp;amp;lt;0.0002 for all dimensions and subjects; group mean correlation coefficients for color, shape and motion targets: 0.57(0.03), 0.57(0.02), 0.47(0.03)). Our results show that target detection times can be altered by trial history, and explainable by a fast-decaying integration of trial history. We propose that trial history modulates attention resulting in response time changes; we are currently investigating this hypothesis using functional neuroimaging. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v060248 Biologische Kybernetik Max-Planck-Gesellschaft St. Petersburg, Russia 29th European Conference on Visual Perception en johannesJSchultz hhbHHBülthoff conference 4224 Perception 2006 8 35 ECVP Abstract Supplement 69 Motion signals projected onto the retina serve many different yet essential behavioral functions: from quickly detecting objects and segmenting them from background clutter, to effectively navigating through a dynamic environment and recognizing and interacting with objects populating that environment. Not surprisingly, computer scientists, psychologists, cognitive scientists, and neuroscientists alike have actively studied the perception and processing of visual motion. Until recently, the general approach has been to investigate mechanisms of motion perception relevant for specific purposes and typically focused at a specific level of processing, such as stimulus- or cognitively-driven mechanisms. Although this approach has greatly extended our knowledge and appreciation of visual motion processing, it is less clear how motion information relates across these different levels. The purpose of this symposium is to bridge the gap between these levels of visual motion processing and foster discussion between re searchers across the various levels. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v060766 Biologische Kybernetik Max-Planck-Gesellschaft St. Petersburg, Russia 29th European Conference on Visual Perception qvuongQCVuong kpilzKSPilz chuangLChuang poster 4873 Abstracts of the 11th Annual Congress of the European College of Sport Science (ECSS Lausanne 2006) 2006 7 11 267-268 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft en SJanda GJendrusch PPlaten ABolsinger MBach kascotKKaulard BLingelbach poster 4007 Journal of Vision 2006 6 6 6 314 Unfamiliar viewpoints can hinder visual object recognition from 2D static images. Here, we ask whether the same is true when visual input is in the form of dynamic spatio-temporal sequences, such as would accompany object or observer motion. Previous research has shown that such motion can be characteristic for a particular object and hence provide additional cues to identity. In two experiments we demonstrate that learned object motion can facilitate recognition across unfamiliar viewpoints. In each experiment, 24 participants were trained to discriminate between two novel amoeboid-like objects seen from a fixed viewpoint. These objects either deformed nonrigidly (Experiment 1) or rotated rigidly about a horizontal axis (Experiment 2). Both types of motion presented the observer with a coherent sequence of change that had a unique temporal order. After training, participants underwent a 2-interval-forced-choice task that tested their ability to discriminate the two learned objects from two novel objects. At test, objects were presented at 0°, 10°, 20° and 30° around the vertical axis relative to the learned viewpoint, and in the learned or reversed temporal order. The manipulation of temporal order has previously been used to study the contribution of motion to object recognition. In both experiments, accuracy decreased with increasing rotations away from the learned viewpoint and there was a constant benefit for learned object motion across all viewpoints tested (Experiment 1 = 4.9%; Experiment 2 = 5.3%). These results indicate that both rigid and non-rigid motion facilitated object recognition despite disturbances in 2D shape by viewpoint changes. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/6/6/314.short?related-urls=yes&legid=jov;6/6/314 Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA 6th Annual Meeting of the Vision Sciences Society (VSS 2006) 10.1167/6.6.314 chuangLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster 4059 Journal of Vision 2006 6 6 6 10 Our previous studies have shown that memory for a face can be affected by the distinctiveness of a voice to which it had been paired (Bülthoff &amp; Newell, ECVP2004). Moreover, we showed that voices can prime face recognition, suggesting a tight, cross-modal coupling between both types of stimuli. Further investigations however, seemed to suggest that non person-related audio stimuli could also affect memory for faces. For example, faces that had been associated with distinctive instrumental sounds were indeed better recognized in an old/new task than faces paired to typical sounds. Here we investigated whether these arbitrary sounds can also prime face recognition. Our results suggest that arbitrary audio stimuli do not prime recognition of faces. This finding suggests that attentional differences may have resulted in better recognition performance for faces paired to distinctive sounds in the explicit old/new task. Voices are easier to associate closely to faces. We also investigated whethe r the voice priming effect found earlier might be based on the use of different first names in each audio stimulus, that is, whether the effect was based on semantic rather than perceptual information. We repeated the priming experiment using the same voice stimuli, but name information was removed. The results show that there is still a significant priming effect of voices to faces, albeit weaker than in the full voice experiment. The semantic information related to the first name helps but is not be decisive for the priming effect of voices on face recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://journalofvision.org/6/6/10/ Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA 6th Annual Meeting of the Vision Sciences Society (VSS 2006) en 10.1167/6.6.10 isaIBülthoff fionaFNNewell article 3769 Quarterly Journal of Experimental Psychology 2006 5 59 5 801-808 It is easier to identify a degraded familiar face when it is shown moving (smiling, talking; nonrigid motion), than when it is displayed as a static image (Knight &amp; Johnston, 1997; Lander, Christie, &amp; Bruce, 1999). Here we explore the theoretical underpinnings of the moving face recognition advantage. In Experiment 1 we show that the identification of personally familiar faces when shown naturally smiling is significantly better than when the person is shown artificially smiling (morphed motion), as a single static neutral image or as a single static smiling image. In Experiment 2 we demonstrate that speeding up the motion significantly impairs the recognition of identity from natural smiles, but has little effect on morphed smiles. We conclude that the recognition advantage for face motion does not reflect a general benefit for motion, but suggests that, for familiar faces, information about their characteristic motion is stored in memory. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.informaworld.com/smpp/ftinterface~content=a746009644~fulltext=713240930 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1080/17470210600576136 KLander chuangLChuang LWickham article 3770 Visual Cognition 2006 5 14 1 85-88 Current theories of visual object recognition tend to focus on static properties, particularly shape. Nonetheless, visual perception is a dynamic experience–as a result of active observers or moving objects. Here, we investigate whether dynamic information can influence visual object-learning. Three learning experiments were conducted that required participants to learn and subsequently recognize different non-rigid objects that deformed over time. Consistent with previous studies of rigid depth-rotation, our results indicate that human observers do represent object-motion. Furthermore, our data suggest that dynamic information could compensate for when static cues are less reliable, for example, as a result of viewpoint variation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.informaworld.com/smpp/ftinterface~content=a747834181~fulltext=713240930 Biologische Kybernetik Max-Planck-Gesellschaft en 10.1080/13506280600627756 chuangLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster 4874 Abstracts of the VISTA 2006 Conference 2006 5 2006 20-21 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.paralympic.org/release/Main_Sections_Menu/IPC_Events/Vista_Conference_2006/2006_04_28_Abstract_Booklet.pdf Biologische Kybernetik Max-Planck-Gesellschaft en GJendrusch ABolsinger SJanda EZrenner MBach kascotKKaulard BLingelbach poster 4828 2006 3 9 69 Theory-of-Mind, or mentalising, is defined as a cognitive process used to understand other peoples’ actions based on mental states. Twomain theories of mentalising have been put forward in recent years: Simulation Theory and Theory-Theory. We propose a model of mentalising based on action prediction and semantic representation. The model would be triggered whenever a human observer detects a potential agent (particularly other humans, but also other animals or active entities). On the basis of their actions, it would associate a possible mental state to the observed agent and predict its future behaviour. To do this, first a search engine would look for a potential mental state matching an observed action in a look-up table containing actionmental state associations acquired through experience. Then, a predictor would calculate a possible next action for the observed agent on the basis of the mental state, and a comparator would compare this predicted action to the actual next action of the agent. If the discrepance between predicted and actual behaviour is greater than a threshold, the mental state is rejected and the process repeated until a conclusive match or abandon. The predictor is postulated to be similar to mechanisms thought to underlie motor learning or reinforcement learning, while the look-up table could resemble semantic representations of objects or faces. The model could also be used for active interaction with other agents: the search engine would find an action to be executed by the observer in order to induce a particular mental state in the observed agent. Success could be assessed by the model through observation of the other agents’ reaction. The neural correlates for this model are likely to be distributed and could include the posterior part of the superior temporal sulcus, the medial prefrontal cortex, the temporal poles, the premotor cortex and the cerebellum. To assess the plausibility of the model and test possible associations between particular neural structures and the components of the model, we review previous studies of the neural correlates of mentalising and some associated processes. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk06/abstract.php?_load_id=schultz01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 9th Tübingen Perception Conference (TWK 2006) en johannesJSchultz Fde Vignemont poster 4829 2006 3 9 72 In this study we ask whether visually typical faces can become perceptually distinctive when they are paired to auditory stimuli that are distinctive. In a first set of experiments (B¨ulthoff & Newell, ECVP 2004), we had investigated the effect of voice distinctiveness on face recognition. Memory for a face can be influenced by the distinctiveness of an utterance to which it has been associated. Furthermore, recognition of a familiar face can be primed by a paired utterance. These findings suggest that there is a tight, cross-modal coupling between the faces presented and the associated utterances and that face distinctiveness can be influenced by crossmodal interaction with auditory stimuli like voices. In another set of experiment, we used instrumental sounds instead of voices and showed that arbitrary auditory stimuli could also affect memory for faces. Faces that had been paired with distinctive instrumental sounds were better recognized in an old/new task than faces paired to typical instrumental sounds. Here we investigated whether these instrumental sounds can also prime face recognition although these auditory stimuli are not associated to faces naturally as voices are. Our results suggest that this is not the case; arbitrary audio stimuli do not prime recognition of faces. This finding suggests that attentional differences may have resulted in better recognition performance for faces paired to distinctive sounds in the old/new task. It also suggests that utterances are easier to associate closely to faces than arbitrary sounds. In a last set of experiments we investigated whether the voice priming effect shown in the first set of experiments might be based on the use of different first names in each utterance. Thus, we asked whether semantic rather than perceptual information was determinant in the used utterances. We repeated the priming experiment using the same voice stimuli, but name information was removed. The results show that there is still a significant priming effect of voices to faces, albeit weaker than in the full voice experiment. The semantic information related to the first name helps but is not be decisive for the priming effect of voices on face recognition. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk06/abstract.php?_load_id=buelthoff01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 9th Tübingen Perception Conference (TWK 2006) en isaIBülthoff fionaFNNewell poster 4839 2006 3 9 118 Recognizing objects across viewpoints presents the visual system with an extremely challenging task. This would be particularly true if learned representations were solely determined by spatial properties. However, a number of recent studies have shown that observers are also highly sensitive to characteristic object motion. Could the availability of characteristic spatial-temporal patterns in the natural environment help explain the ability to generalise across viewpoints? Here, we examined how familiar object motion (both rigid and nonrigid) improves object recognition across different viewpoints. In both experiments, participants were first familiarised with two novel dynamic objects from a fixed viewpoint. These objects presented the observer with a coherent sequence of change that had a unique temporal order, resulting from either rotating a rigid object about the horizontal axis (Experiment 1) or through a characteristic deformation of a nonrigid object (Experiment 2). Subsequently, participants were tested for their ability to discriminate these learned objects from new distractors using a 2-interval-forced-choice task. During test, objects were presented at 0°, 10°, 20° and 30° around the vertical axis relative to the learned viewpoint, and in the learned or reversed temporal order. Motion reversal is a common manipulation used to disrupt spatiotemporal properties, without interfering with the object’s spatial characteristics. In both experiments, accuracy decreased with increasing variance from the learned viewpoint. Nonetheless, objects were consistently better recognised when presented in the learned motion sequence (mean accuracy: Expt 1 = 86%; Expt 2 = 81%)compared to the reverse motion condition (mean accuracy: Expt 1 = 81%; Expt 2 = 76%), across all viewpoints tested (Expt 1: F(1,23)=13.94, p<0.01; Expt 2: F(1,23)=8.78, p<0.01). These results indicate that both rigid and non-rigid motion facilitated object recognition despite disturbances in 2D shape by viewpoint changes. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk06/abstract.php?_load_id=chuang01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 9th Tübingen Perception Conference (TWK 2006) en chuangLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster 4847 2006 3 9 172 Previous studies (Atick and Redlich, Field, Webster and Miyahara) have investigated how the visual system could optimally represent the 1/f amplitude spectrum of natural images. Computational studies (Atick and Redlich, Field) suggest that the cortical representation ought to be a “whitened” version of the amplitude spectrum of natural images, i.e. spatial frequencies are equally represented despite the abundance of low spatial frequencies and dearth of high spatial frequencies in photographs of real world scenes. Webster and Miyahara showed that adaptation to natural images attenuates sensitivity to low spatial frequencies effectively supporting the computational evidence. We attempt to measure to what degree different spatial frequencies contribute to the percept of an image, in order to determine the extent of whitening of the input. To do this we adapted subjects briefly (250ms) to textures (4 x 4 degrees) of different spatial frequencies (1, 2, 4, 8, 16 cycles/degree, bandwidth 1.4 octaves—full width at half maximum). Then we measured the perceived contrast of 1/f textures in the adapted region of the visual field using the following procedure: After each interval of adaptation subjects judged whether the texture in the adapted region had a higher or lower contrast than that of the same texture in a non-adapted region. The contrast of the comparator texture (non-adapted) was changed after each time the subject made a judgement according to a 1 up 1 down staircase. We found that attenuation of perceived contrast, due to adaptation, is greatest when the adapting frequencies are at the peak of the contrast sensitivity function. It seems there is some “whitening”; however this is, at best, incomplete. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk06/abstract.php?_load_id=mcdonald01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 9th Tübingen Perception Conference (TWK 2006) en jsmJSMcDonald johannesJSchultz conference 3815 2006 1 Investigating face recognition with voices and face morphs Humans can easily identify faces at the individual level although faces belong to a class of objects with high similarity between exemplars. Characterizing conditions for which faces are more easily recognized allows us to better understand the mechanisms underlying face recognition. Numerous studies have shown that distinctive faces are better recognized than typical faces. Those results have implication for the mental representation of faces. In a set of experiments we tested cross-modal effects of distinctiveness. More specifically we asked whether distinctive voices can improve memory for otherwise typical faces. Our results suggest that the quality of information in one modality, i.e., audition, can affect recognition in another modality, i.e., vision; thus showing that face distinctiveness can be of multi-modal nature. Because we encounter faces of only two sexes but recognize faces of innumerable different identities, it is often implicitly assumed that sex classification is an easier task than identification. We investigated how sensitive we are to variations of identity-related features or sex-related features of highly familiar faces. The results suggest that while extracting and processing sex-related information from a face is a comparatively easy task, we do not seem to retain sex-related facial information in memory as accurately as identity-related information. These results have implications for models of face representation and face processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Gemany Face Mini-Symposium: Georg-August-Universität Göttingen, Zentrum für Neurobiologie des Verhaltens en isaIBülthoff article 4871 BISp-Jahrbuch Forschungsförderung 2006 2005/06 83-88 Im Sinne einer ersten Bestandsaufnahme wurden zunächst Sehtestergebnisse und ophthalmologische Befunde sowie Klassifizierungsergebnisse, die vor/bei internationalen Wettkämpfen der Sehbehinderten (Paralympics, Weltmeisterschaften etc.) erhoben wurden, ausgewertet. Dabei wurden Unterschiede in den visuellen Leistungsprofilen (Visus, Gesichtsfeld) und den ophthalmologischen Befunden in den verschiedenen Startklassen (B1-B3) und Sportarten analysiert. Da die Klassifizierung von Sehbehinderungen bisher größtenteils visusbasiert ist, das zur Sehschärfebestimmung eingesetzte Verfahren (die S.O.S.H.-Low Vision Chart (S.O.S.H. = Student Optometric Service to Humanity); vgl. Sehprobentafel in Abb. 1, links) aber nicht der Europäischen Norm EN ISO 8596 entspricht, wurde im Rahmen der Internationalen Deutschen Meisterschaft der Leichtathletik in Berlin (2005) sowie der Qualifikationsrunde zur Deutschen Meisterschaft im Torball in Kassel (2006) versucht, modernere computerunterstützte (automatisierte) und normenkonforme Verfahren zur Visusbestimmung zu erproben. Da neben der Sehschärfe im Sport vor allem das Kontrastsehen, das Dynamische Sehen und das Periphere Sehen von großer Bedeutung sind (Mester, 1988; Tidow, 1996; Jendrusch, 1995; Jendrusch & Brach, 2003), die bei der Klassifizierung bisher aber unberücksichtigt bleiben, wurden ferner weitere neu entwickelte Verfahren zur visuellen Leistungsdiagnostik erprobt. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.bisp.de/cln_050/nn_113306/SharedDocs/Downloads/Publikationen/Jahrbuch/Jb__200506__Artikel/Heck,templateId=raw,property=publicationFile.pdf/Heck.pdf Biologische Kybernetik Max-Planck-Gesellschaft de GJendrusch ABolsinger SJanda MBach kascotKKaulard BLingelbach HHeck inbook 3351 2006 165-172 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Handbuch_der_allgemeinen_Psychologie_165-172_middle_3351[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://books.google.de/books/about/Handbuch_der_Allgemeinen_Psychologie_Kog.html?id=cY0QAQAAIAAJ&redir_esc=y Funke, J. , P. A. Frensch Hogrefe

Göttingen, Germany

Handbuch der Psychologie ; 5 Handbuch der Allgemeinen Psychologie: Kognition Biologische Kybernetik Max-Planck-Gesellschaft de 978-3-8017-1846-6 isaIBülthoff hhbHHBülthoff conference 3771 2005 11 9 13 3 Current theories of visual object recognition tend to focus on static properties, particularly shape. Nonetheless, visual perception is a dynamic experience–as a result of active observers or moving objects. Here, we investigate whether dynamic information can influence visual object-learning. Three learning experiments were conducted that required participants to learn and subsequently recognize different non-rigid objects that deformed over time. Consistent with previous studies of rigid depth-rotation, our results indicate that human observers do represent object-motion. Furthermore, our data suggest that dynamic information could compensate for when static cues are less reliable, for example, as a result of viewpoint variation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.opam.net/opam2005/ Biologische Kybernetik Max-Planck-Gesellschaft Toronto, Canada 13th Annual Workshop on Object Perception, Attention, and Memory (OPAM 2005) en chuangLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster 3811 2005 11 35 877.14 Theory-of-Mind, or mentalising, is defined as a cognitive process used to understand other peoples' actions based on mental states. Two main theories of mentalising have been much discussed in recent years: Simulation Theory (e.g. Goldman 1993; Gallese and Goldman 1998), and Theory-Theory (e.g. Gopnik 1993). Models derived from these ideas and integrating neuroscience findings have been proposed since (e.g. Frith and Frith 1999; Blakemore and Decety 2001; Wolpert, Doya and Kawato 2003). Here we use the main idea from one of these models (Wolpert et al 2003) to propose a tentative model of mentalising based on action prediction and semantic representation. We also review a few neuroimaging studies of the processes involved in the model. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/SfN2005poster_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.sfn.org/index.aspx?pagename=neuroscienceQuarterly_05summer_ns2005preview Biologische Kybernetik Max-Planck-Gesellschaft Washington, DC, USA 35th Annual Meeting of the Society for Neuroscience (Neuroscience 2005) johannesJSchultz Fde Vignemont techreport 3637 2005 10 094 We investigated whether male and female faces are discrete categories at the perceptual level. We created artificial gender continua between male and female faces using a 3D-morphing algorithm and used classical categorization and discrimination tasks to investigate categorical perception of gender. In Experiments 1 and 3, 3D morphs were computed between male and female faces. The results of the discrimination task suggest that the gender of unfamiliar faces is not categorically perceived. When participants were familiarized with the male and female endpoint faces before testing (Experiment 3), a categorical effect was found. In Experiment 2, only shape or texture of unfamiliar 3D morphs was indicative of gender, while other information (e.g. texture or shape) was kept constant. Again there was no evidence of a categorical effect in the discrimination task. In Experiments 1, 2 and 3, changes in the gender of a face were also coupled with changes in identity which may have confounded the findings. In Experiments 4 and 5, we used face continua in which only the gender of the facial features changed, while the characteristic of the facial features remained constant. When the faces were unfamiliar (Experiment 4), there was no evidence of categorical perception of gender. In Experiment 5, participants learned to classify the face images in two gender categories using a feedback procedure. A clear categorical effect for gender was present after training. Our findings suggest that despite the importance of faces, gender information present in faces is not naturally perceived categorically. Consequently participants showed categorical perception of gender only after training with the face stimulus set. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/techreport_094_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics, Tübingen, Germany en isaIBülthoff fionaFNNewell conference 3590 Journal of Vision 2005 9 5 8 379 Because we encounter faces of only two sexes but recognize faces of innumerable different identities, it is often implicitly assumed that sex determination is easier than identification in face recognition. Many studies support this assumption. For example, we are very accurate at telling the sex of unfamiliar faces in photographs (Bruce, et al., 1993. Perception, 22, 131–52) and sex categorization is performed more rapidly, on average, than familiarity or identity decisions (Bruyer, Galvez, & Prairial, 1993. British Journal of Psychology, 84, 433–441). The question that we investigated here is how sensitive we are to variations of identity-related features or sex-related features in familiar faces. 38 participants had to pick out the veridical faces of ten familiar work colleagues from amongst distractor faces that were variations of the original faces. Distractor faces varied either in identity, caricature or sex. In the identity face sets, distractor faces were various morphs between the original face and two unfamiliar faces. In the caricature face sets, distractors were various caricatures of the original face. Finally, in the sex face sets, distractor faces were various feminized and masculinized versions of the original face. Participants were most accurate at identifying the original face amongst distractors in the identity sets. They had a tendency to choose positive caricatures over the original faces in caricature sets. However, participants were very poor at finding the original faces in the sex sets. The results suggest that while extracting and processing sex-related information from a face is a comparatively easy task, we do not seem to retain sex-related facial information in memory as accurately as identity-related information. These results have implications for models of face representation and face processing. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://journalofvision.org/5/8/379/ Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA Fifth Annual Meeting of the Vision Sciences Society (VSS 2005) en 10.1167/5.8.379 isaIBülthoff fionaFNewell conference Chuang2005 2005 9 6 8 Studies in the field of visual object recognition generally report observed human performance with 2D still images e.g. photographs, line-drawings. One of the main reasons for doing so stems from the ready availability of such stimuli for experimentation (for example, see http://www.cog.brown.edu/~tarr/projects/databank.html). Human visual perception, however, is a dynamic process - as the result of either an active observer or a moving target, the visual experience is rarely static. Hence, it is important to question whether such findings realistically portray daily human behavior. Recent experiments using dynamic stimuli have shown that human performance can differ as a result of introducing natural motion information to the studied object; for example, there is a recognition benefit for when faces are seen moving (e.g., Toole et al, 2002). Such evidence clearly suggests that object motion plays a non-trivial role in visual recognition. Nonetheless, there are challenges - both technical and experimental - that a researcher ought to consider when using dynamic stimuli. Here, I will discuss some of these issues as well as the steps that were adopted, in my research, to overcome them. In particular, I will describe how different types of dynamic stimuli could be generated for various experiments in novel object and face learning, as well as some of software and hardware available for this undertaking. In addition, I will briefly discuss how such stimuli could be presented in psychophysical experiments, such as to control for possible artifacts e.g., timing errors. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.neuroschool-tuebingen-nena.de/index.php?id=284 Blaubeuren, Germany 6. Neurowissenschaftliche Nachwuchskonferenz Tübingen (NeNa '05) chuangLChuang inproceedings 3450 Proceedings of the 2nd Symposium on Applied Perception in Graphics and Visualization (APGV&lsquo;05) 2005 8 158-158 Human visual recognition can be improved with object motion (e.g., faces, Lander and Chuang, 2005; rigid objects, Vuong and Tarr, 2004) This improvement suggests that it is not merely shape information that characterizes an object. Rather, human observers may also represent how shape changes over time for recognition. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf3450.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://portal.acm.org/citation.cfm?id=1080438 Spencer, S.N. ACM Press

New York, NY, USA

Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics, Tuebingen A Coruna, Spain 2nd Symposium on Applied Perception in Graphics and Visualization (APGV 2005) en 1-59593-139-2 10.1145/1080402.1080438 chuangLChuang qvuongQCVuong ianIMThornton hhbHHBülthoff poster SchultzFWF2005 Perception 2005 8 34 ECVP Abstract Supplement 62 An essential, evolutionarily stable feature of brain function is the detection of animate entities, and one of the main cues to identify them is their movement. We developed a model of a simple interaction between two objects, in which we could control the percept of animacy by varying one parameter. The two disk-like objects moved along separate random trajectories but were also influenced by each other's positions, such that one object followed the other, in a parametrically controlled fashion. An increase of the correlation between the object's movements varied the amount of interactivity and animacy observers attributed to them. Control animations were only different from the experimental in terms of the interactivity level, but not in terms of object speed and separation. Twelve observers lying in a magnetic-resonance-imaging scanner had to rate the amount of interactivity and the overall speed of the objects in separate, subsequent tasks. Behavioural results showed a significant difference in interactivity ratings between experimental and control stimuli, but no difference in speed ratings, as expected. There was no response-time difference between the tasks. The fMRI data revealed that activation in the posterior superior temporal sulcus and gyrus (pSTS/pSTG) increased in relation to the degree of correlated motion between the two objects. This activation increase was not different when subjects performed an explicit or implicit task while observing these interacting objects. These data suggest that the pSTS and pSTG play a role in the automatic identification of animate entities, by responding directly to an objective movement characteristic inducing the percept of animacy, such as the amount of interactivity between two moving objects. These findings are consistent with literature showing that, in monkey and human, pSTS and pSTG respond to stimuli displaying biological motion. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v050631 A Coruña, Spain 28th European Conference on Visual Perception johannesJSchultz KJFriston DMWolpert CDFrith poster 4004 Perception 2005 8 34 ECVP Abstract Supplement 130 Object motion, eg depth-rotation, provides visual information that might be useful for the reconstruction of an object's 3-D structure, hence increasing the recognition likelihood of any given moving object. Our aim is to demonstrate that object motion can, in itself, serve as an independent cue to object identity without particular recourse to form-retrieval processes. In this study, we used novel amoeboid objects that transformed nonrigidly over time. Two experiments are reported on the learnt recognition of such stimuli. During an initial study phase, participants learnt to identify these objects. At test, participants were either presented with an old/new recognition task (experiment 1) or with a two-alternative forced-choice task (experiment 2). Here, learnt stimuli were presented in either the studied sequence of shape transformations, or the reverse order. Although the shapes shown were the same in both instances, the overall findings indicate that participants performed significantly better in recognising the learnt objects when the same shapes were presented in the learnt sequence, than when they were presented in reverse sequence. If object motion facilitates recognition of the stimulus solely by contributing to the recovery of its form, the sequence of non-rigid transformation would not be relevant to its representation. Nonetheless, these findings suggest that human observers do not merely remember a visual object as a collection of different shapes. Instead, observers are also sensitive to how these shapes transform over time. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v050140 http://ecvp2005.neuralcorrelate.com/ Biologische Kybernetik Max-Planck-Gesellschaft A Coruña, Spain 28th European Conference on Visual Perception chuangLChuang qvuongQCVuong ianIMThornton conference 3772 2005 8 Previous research has typically focused on static properties of objects. Recently there has been a growing interest in the role that dynamic information might play in the perception and representation of objects. In this talk we approach this issue by describing how the visual system utilises dynamic information in learning two different classes of visual objects: i) novel deforming stimuli, ii) faces. Object-learning experiments with novel objects show that human observers are sensitive to the motion characteristics. In addition, preliminary results also suggest that learned motion characteristics can reduce the detrimental effects of changing the studied viewpoint. Using faces, we explored how encoding of identity is affected by two different types of facial movements: non-rigid facial motion, and looming facial motion. Using a delayed visual search paradigm we could show that faces learned in motion were found more quickly and more accurately than faces learned from static snapshots. In summary, results from our lab suggest that the visual system uses dynamic information to encode and subsequently recognize new object/face identities. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Cardiff, UK Sensational Seminar Series, School of Psychology, Cardiff University en chuangLChuang conference 3813 Perception 2005 8 34 ECVP Abstract Supplement 21 Even though shape is the basis of object recognition, there is still an on-going debate about how it is perceived and represented in the brain. An important question is how various visual cues, like disparity and texture, are integrated into a unique shape percept. Different visual information has also been shown to play an ancillary role in shape perception. For example, cast shadows can help disambiguate shape perception (Kersten et al, 1996 Nature 379 31) while 2D retinal motion information can help organize dots into meaningful shapes despite incongruent depth information (Bülthoff et al, 1998 Nature Neuroscience 1 254 - 257). Shape perception is also important for object categorization. For example, faces varying in shape and texture may be perceptually grouped into different categories (a phenomenon known as categorical perception). Previous studies have shown that faces varying in expressions, identity or race are perceived categorically (e.g. Levin &amp;amp;amp;amp;amp;amp; Angelone, 2002 Perception 31 567 - 578). We did not find similar effect for faces varying in masculinity/feminity (Bülthoff &amp;amp;amp;amp;amp;amp; Newell, 2004 Visual Cognition 11 823 - 855). This difference in perception for sex and identity is supported by new studies showing a lack of sensitivity to sex changes in familiar faces, while changes in identity are easily noticed. These results have implications for the nature of shape representations of faces in the brain. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v050008 Biologische Kybernetik Max-Planck-Gesellschaft A Coruña, Spain 28th European Conference on Visual Perception en isaIBülthoff article 2929 Visual Cognition 2005 4 12 3 429-442 Previous work has suggested that seeing a famous face move aids the recognition of identity, especially when viewing conditions are degraded (Knight & Johnston, 1997; Lander, Christie, & Bruce, 1999). Experiment 1 investigated whether the beneficial effects of motion are related to a particular type of facial motion (expressing, talking, or rigid motion). Results showed a significant beneficial effect of both expressive and talking movements, but no advantage for rigid motion, compared with a single static image. Experiment 2 investigated whether the advantage for motion is uniform across identity. Participants rated moving famous faces for distinctiveness of motion. The famous faces (moving and static freeze frame) were then used as stimuli in a recognition task. The advantage for face motion was significant only when the motion displayed was distinctive. Results suggest that a reason why moving faces are easier to recognize is because some familiar faces have characteristic motion patterns, which act as an additional cue to identity. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf2929.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.informaworld.com/smpp/6084610-9322645/ftinterface~content=a713734696~fulltext=713240930~frm=content Biologische Kybernetik Max-Planck-Gesellschaft University of Manchester, Manchester, UK en 10.1080/13506280444000382 KLander chuangLChuang conference 3773 2005 3 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk Biologische Kybernetik Max-Planck-Gesellschaft Manchester, UK Brainstorming Colloquium, Department of Psychology, University of Manchester en chuangLChuang qvuongQCVuong ianIThornton article 3063 Neuron 2005 2 45 4 625-635 An essential, evolutionarily stable feature of brain function is the detection of animate entities, and one of the main cues to identify them is their movement. We developed a model of a simple interaction between two objects, in which an increase of the correlation between their movements varied the amount of interactivity and animacy observers attributed to them. Functional magnetic resonance imaging revealed that activation in the posterior superior temporal sulcus and gyrus (pSTS / pSTG) increased in relation to the degree of correlated motion between the two objects. This activation increase was not different when subjects performed an explicit or implicit task while observing these interacting objects. These data suggest that the pSTS and pSTG play a role in the automatic identification of animate entities, by responding directly to an objective movement characteristic inducing the percept of animacy, such as the amount of interactivity between two moving objects. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf3063.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.neuron.2004.12.052 johannesJSchultz KFriston DWolpert CFrith poster 5075 ASLO Aquatic Sciences Meeting 2005 2 1 1 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft en MSieracki ERiseman WBalch MBenfield AHanson CPilskaln HSchultz CSieracki PUtgoff blaschkoMBlaschko GHolness MMattar DLisin BTupper poster 3301 2005 2 8 124 It is known that we are quite accurate at judging the sex of unfamiliar faces [1]. Furthermore sex categorization is performed more rapidly, on average, than familiarity or identity decisions [2]. In one of our recent studies on face perception, with unfamiliar faces [3] we were surprised to find that discrimination performance was much lower for faces differing in sex quality than when the facial features were morphed between two identities. Here, we investigated if this observation holds also for familiar faces. The motivation for this series of experiments was to find out if memory of familiar faces was showing similar differences; participants being more inaccurate when they had to remember the specific feminity or masculinity of a well known face than when identity-related changes of facial features were involved. Participants had to identify the veridical faces of familiar work colleagues among ten distractor faces that were morphing variations of the original faces. Distractor faces varied either in identity, caricature or sex. In the identity face sets, distractor faces were morphs between the original face and unfamiliar faces mixed in different proportions. In the caricature face sets, distractors were different caricatures of the original face. Finally, in the sex face sets, distractor faces were different feminized and masculinized versions of the veridical face. Participants performed best when the original face was presented among identity distractors. They had a tendency to choose feature enhancing caricatures over the original faces in caricature sets. Participants were very poor at finding the original faces in the sex sets. Generally our findings with unfamiliar faces show that sex-related changes in facial features are less obvious to the observers than identity-related changes. Furthermore our study on familiar faces suggests that we do not retain sex-related facial information in memory as accurately as identity-related information. These results have important implications for models of face recognition and how facial features are represented in the brain. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk05/programm.php Bülthoff, H. H., H. A. Mallot, R. Ulrich and F. A. Wichmann Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 8th Tübingen Perception Conference (TWK 2005) isaIBülthoff inproceedings 5073 Proceedings of the Seventh IEEE Workshops on Application of Computer Vision (WACV/MOTION&lsquo;05) 2005 1 79 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de WACV Biologische Kybernetik Max-Planck-Gesellschaft WACV en blaschkoMBBlaschko GHolness MAMattar DLisin PEUtgoff ARHanson HSchultz EMRiseman MESieracki WMBalch BTupper article 3062 Journal of Cognitive Neuroscience 2004 12 16 10 1695-1705 Previous functional imaging experiments in humans showed activation increases in the posterior superior temporal gyrus and sulcus during observation of geometrical shapes whose movements appear intentional or goal-directed. We modeled a chase scenario between two objects, in which the chasing object used different strategies to reach the target object: the chaser either followed the target’s path or appeared to predict its end position. Activation in the superior temporal gyrus of human observers was greater when the chaser adopted a predict rather than a follow strategy. Attending to the chaser’s strategy induced slightly greater activation in the left superior temporal gyrus than attending to the outcome of the chase. These data implicate the superior temporal gyrus in the identification of objects displaying complex goal-directed motion. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf3062.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft en 10.1162/0898929042947874 johannesJSchultz HImamizu MKawato CFrith article 2385 Visual Cognition 2004 10 11 7 823-855 We investigated whether male and female faces are discrete categories at the perceptual level and whether familiarization plays a role in the categorical perception of sex. We created artificial sex continua between male and female faces using a 3‐D morphing algorithm and used classical categorization and discrimination tasks to investigate categorical perception of sex. In Experiments 1 and 2, 3‐D morphs were computed between individual male and female faces. In Experiments 3 and 4, we used face continua in which only the sex of the facial features changed, while the identity characteristics of the facial features remained constant. When the faces were unfamiliar (Experiments 1 and 3), we failed to find evidence for categorical perception of sex. In Experiments 2 and 4, we familiarized participants with the individual face images by instructing participants to learn the names of the individuals in the endpoint face images (Experiment 2) or to classify face images along a continuum as male or female using a feedback procedure (Experiment 4). In both these experiments we found evidence for a categorical effect for sex after familiarization. Our findings suggest that despite the importance of face perception in our everyday world, sex information present in faces is not naturally perceived categorically. Categorical perception of sex was only found after training with the face stimulus set. Our findings have implications for functional models of face processing which suggest two independent processing routes, one for facial expression and one for identity: We propose that sex perception is closely linked with the processing of facial identity. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/categorical_perception_of_sex_occurs_in_familiar_but_not_infamiliar_faces_2385[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.tandfonline.com/doi/abs/10.1080/13506280444000012 Biologische Kybernetik Max-Planck-Gesellschaft 10.1080/13506280444000012 isaIBülthoff fionaFNewell article 3064 Behavioural and Brain Sciences 2004 10 27 5 674-675 We suggest that certain experiences reported by patients with schizophrenia show that priority, consistency, and exclusivity are not sufficient for the experience of willing an action. Furthermore, we argue that even if priority, consistency, and exclusivity cause the experience of being the author of an action, this does not mean that conscious will is an illusion. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/PrecisWegnerCommentBBS2004_3064[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://journals.cambridge.org/production/action/cjoGetFulltext?fulltextid=287794 Biologische Kybernetik Max-Planck-Gesellschaft en johannesJSchultz NSebanz CFrith poster 3188 2004 10 34 664.1 The cortex surrounding the posterior superior temporal sulcus of humans and monkeys is known to be activated during observation of biological movements, including human actions (1,2). In our event-related fMRI experiment, 12 healthy human volunteers were asked to discriminate between 2 versions of four different human actions on the basis of their movement kinematics. The difficulty of the task was influenced by the number of joints showing differences between the two movement versions. Clusters in the posterior superior temporal sulcus region in both hemispheres were the only brain regions whose activity varied inversely with the number of joints with significant differences between the two movement versions (clusters identified by SPM RFX analysis with 12 subjects thresholded at p<0.001 uncorrected, correlation with activation in left STS: R² = 0.96, right STS: R²= 0.94). Activity in the cluster identified in the right posterior superior temporal sulcus also showed a trend to correlate positively with participants’ performance (non significant, p=0.13). These results suggest that the cortex surrounding the posterior superior temporal sulcus participates in the extraction of kinematic information from observed biological movements, with activity increasing with task difficulty. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sfn.org/absarchive/ Biologische Kybernetik Max-Planck-Gesellschaft San Diego, CA, USA 34th Annual Meeting of the Society for Neuroscience (Neuroscience 2004) johannesJSchultz JNIngram DMWolpert CDFrith poster 3067 Perception 2004 8 33 ECVP 2004 Abstract Supplement 108 We can recognise distinctive faces more easily than typical ones. We investigated whether this distinctiveness effect appears for visually typical faces when these faces have been associated with features that are distinctive in another sensory modality. Participants first learned a set of unfamiliar faces. During learning, half of these faces were paired with distinctive auditory stimuli and half with typical stimuli. In experiment 1, the auditory stimuli were voices. We found that recognition performance in a visual recognition test was significantly (p < 0.005) better for faces that had been paired with distinctive voices. In experiment 2, we tested whether voice information improved face recognition directly by association or whether distinctiveness effects were due to enhanced attention during learning. In a priming experiment, participants recognised a face significantly faster (p <0.05) when this face was preceded by its congruent voice. Thus the quality of auditory information can affect recognition in another modality like vision. In experiment 3, the stimuli consisted of non-speech sounds. In this experiment, we tested whether voices and faces represent a special case of cross-modal memory enhancement or whether this distinctiveness effect occurs also with more arbitrary associations. Recognition performance in a visual recognition test suggests that a similar effect is present. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v040398 Biologische Kybernetik Max-Planck-Gesellschaft Max-Planck-Institut für biologische Kybernetik; Trinity College, Ireland, Tübingen, Germany; Budapest, Hungary 27th European Conference on Visual Perception en isaIBülthoff fionaFNNewell conference 3066 Journal of Vision 2004 8 4 8 139 Face recognition studies have shown that distinctiveness can improve recognition. Distinctiveness effects have also been found in stimuli other than faces suggesting that it is a general mechanism. Here we tested cross-modal effects of distinctiveness and asked whether distinctive voices can improve memory for otherwise typical faces. In all experiments participants first learned a set of static, unfamiliar faces. During learning, half of these faces were paired with distinctive voices and half were paired with typical voices. Face stimuli were counterbalanced across these voice conditions. In Experiment 1 we found that recognition performance in a visual recognition test was significantly (p http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://journalofvision.org/4/8/139/ Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA Fourth Annual Meeting of the Vision Sciences Society (VSS 2004) 10.1167/4.8.139 isaIBülthoff fionaFNNewell poster 3189 NeuroImage 2004 6 22 Supplement 1 e2122 Background Behavioural studies of children and adults show that goal-directedness is an important cue for the attribution of animacy to elements of the environment. In monkey and human, the cortex surrounding the superior temporal sulcus (STS) and gyrus (STG) is known to respond to biological motion and to intentional actions [1], and could thus participate in the detection of animate entities [2]. A growing number of neuroimaging studies also indicate that the STS appears to be involved in the representation of mental states. We reasoned that if the STS and STG are sensitive to intentional motion, activation in these structures would vary with the amount of perceived goal-directed motion. Further, if the STS is involved in the attribution of mental states, this structure might respond more when an observed goal-directed behaviour is directed by a representation of the target’s goal rather than a representation of the target’s position. Also, previous studies revealed attention effects on activation of the STS during processing of biological motion and of socially relevant characteristics of a face. Which level of processing in the STS is affected by attention is not yet clear. Methods We devised two fMRI experiments to study the response of the STS and of other brain regions to goal-directedness and the role of attention on this process. We presented healthy adult volunteers with animations of two round shapes moving in a seemingly animate way. In experiment 1, we parametrically varied the amount of goal-directed motion of the two abstract moving objects. Subjects had either to rate the amount of interaction between the moving objects or their speed, which was manipulated independently. In experiment 2, we manipulated the strategy used to reach the goal: agents either seemed to use knowledge of the goals attributed to the target object or to follow the target object. Stimuli were controlled for speed and quantity of movement, and eye movements were monitored in experiment 1. Results Increase in goal-directed behaviour parametrically increased activation in STS/STG and also in the medial occipital cortex and fusiform gyrus, even when subjects performed an incidental task. In experiment 2, watching agents trying to reach targets by using knowledge about the goals of the target object increased activation in the STS/STG, but only when subjects payed attention to the chaser’s strategy and not to the outcome of the chase. Conclusion We conclude that 1) the cortex in the STS/STG region responds to goal-directed behaviour independently of the task performed by the subject, and 2) it reponds more when a chase appears to be directed by a representation of the target’s goal rather than the target’s position, but only when subjects explicitly look for strategies of the chaser. This suggests that only higher levels of processing of socially relevant characteristics are under the influence of attention. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/article/pii/S1053811905700197 Biologische Kybernetik Max-Planck-Gesellschaft Budapest, Hungary 10th Annual Meeting of the Organization for Human Brain Mapping (HBM 2004) 10.1016/S1053-8119(05)70019-7 johannesJSchultz KFriston HImamizu CFrith article 3061 Science 2004 4 304 5669 452-454 Instrumental conditioning studies how animals and humans choose actions appropriate to the affective structure of an environment. According to recent reinforcement learning models, two distinct components are involved: a "critic," which learns to predict future reward, and an "actor," which maintains information about the rewarding outcomes of actions to enable better ones to be chosen more frequently. We scanned human participants with functional magnetic resonance imaging while they engaged in instrumental conditioning. Our results suggest partly dissociable contributions of the ventral and dorsal striatum, with the former corresponding to the critic and the latter corresponding to the actor. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencemag.org/content/304/5669/452.full.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1126/science.1094285 JO'Doherty PDayan johannesJSchultz RDeichmann KFriston RJDolan poster 2631 2004 2 7 122 Studies of visual size perception with the method of magnitude estimation have shown a linear relationship between actual sizes and magnitude estimates [1]. Similar studies for touch do not yield unequivocal evidence for a linear relationship; in some cases, a positively accelerated power function described best the relationship between stimulus sizes and estimates [2]. We have investigated haptic magnitude estimation for length in two haptic experiments with different methods of haptic exploration (whole hand, nger span). The haptic stimuli consisted of 15 rectangular shapes. The only difference from one shape to another was the length of the horizontal side, which ranged from 40 mm to 68 mm in equal intervals. For all shapes, the depth and height were 10 mm and 40 mm, respectively. In the Multiple cues Experiment, blindfolded participants used their dominant hand to feel each shape freely. The shape was presented xed at onto a support, so they could feel the entire shape under their hand. The participants' task was to give a modulus-free magnitude estimate for the horizontal side. All shapes were presented once in random order in each block. In the Single cue Experiment, blindfolded participants were restricted to grasping the horizontal side of a shape between the thumb and index nger of their dominant hand. Their task was to give a magnitude estimate for the length of that side. Magnitude estimates for side length could be tted by a two-parameter linear function with a high goodness-of-t statistic in both experiments (R2 ' .97). Thus, when participants were given a size range of 40 to 68 mm, their magnitude estimates increased linearly with each physical increment, independently of the exploration method used. Because of the small range of total size variation present in the shape set, we do not conclude from our results that haptic magnitude estimation of unidimensional size is generally linear. It should be noted that the present linear functions had a negative y-intercept and that when a power function was t to the data, the exponent was greater than 1.0 in both experiments, and goodness-of-t was also high. Our results suggest, however, that haptic perception of size can safely be considered linear within this small part of the size continuum. These results are important for considering further psychophysical studies with shapes within this size range. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk04/index.php Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 7th Tübingen Perception Conference (TWK 2004) en isaIBülthoff bobbyRLKlatzky fionaFNNewell conference 2932 2004 1 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft ATR Laboratories, Japan 76th Vision Seminar KLander chuangLChuang VBruce thesis 3065 2004 http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/Schultz-Johannes-PhD.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft Wellcome Department of Imaging Neuroscience, University College London PhD johannesJWRSchultz poster 2630 2003 11 44 57 Face studies have shown that distinctive faces are more easily recognized than typical faces in memory tasks. We investigated whether a cross-modal interaction between auditory and visual stimuli exists for face distinctiveness. During training, participants were presented with faces from two sets. In one set all faces were accompanied by characteristic auditory stimuli (d-faces). In the other set, all faces were accompanied by typical auditory stimuli (s-faces). Face stimuli were counterbalanced across auditory conditions. We measured recognition performance in an old/new recognition task. Face recognition alone was tested. Our results show that participants were significantly better (t(12) = 3.89, p< 0.005) at recognizing d-faces than s-faces in the test session. These results show that there is an interaction between different sensory inputs and that typicality of stimuli in one modality can be modified by concomitantly presented stimuli in other sensory modalities. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.psychonomic.org/past-meeting.html Biologische Kybernetik Max-Planck-Gesellschaft Vancouver, Canada 44th Annual Meeting of The Psychonomic Society isaIBülthoff fionaFNNewell hhbHHBülthoff poster 3190 2003 11 33 86.16 Goal-directed behaviour is an important cue for the attribution of animacy to elements of the environment, as has been repeatedly shown in behavioural studies of children and adults. In monkey and human, the superior temporal sulcus (STS) and gyrus (STG) are known to respond to stimuli displaying biological motion, and could thus participate in the detection of living entities. As goal-directedness is important for the attribution of animacy, we expected STS and STG to respond when objects appearing animate try to reach a goal. As the STS also appears to be involved in tasks involving mentalizing, it might also be sensitive to the way the agents reach their goal. In two fMRI experiments, we presented healthy adult volunteers with two agents (interacting, round shapes moving in a seemingly animate way) and varied the goal-directedness in their behaviour. In exp. 1, we parametrically increased the goal-directedness in the interaction of the agents, and in exp. 2 we varied the strategy used to reach the goal: agents either seemed to rely on mentalizing or only on physical cues. Stimuli were controlled for speed and quantity of movement. Increase in goal-directed behaviour parametrically increased activation in STS and STG, even when subjects performed an incidental task. In exp. 2, watching agents using a mentalizing strategy increased activation in the STS and STG; this was reduced when subjects performed an incidental task. We conclude that 1) the STS / STG region responds to goal-directed behaviour independently of the task performed by the subject, and 2) it reponds more when the goal-directed behaviour is apparently relying on mentalizing. This second activation increase seems to be only significant when subjects explicitly look for mental states in the observed behaviour. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sfn.org/index.aspx?pagename=annualmeeting_futureandpast Biologische Kybernetik Max-Planck-Gesellschaft New Orleans, LA, USA 33rd Annual Meeting of the Society for Neuroscience (Neuroscience 2003) johannesJSchultz KJFriston HImamizu CDFrith poster BulthoffN2003_2 Journal of Vision 2003 10 3 9 825 Many face studies have shown that in memory tasks, distinctive faces are more easily recognized than typical faces. All these studies were performed with visual information only. We investigated whether a cross-modal interaction between auditory and visual stimuli exists for face distinctiveness. Our experimental question was: Can visually typical faces become perceptually distinctive when they are accompanied by voice stimuli that are distinctive? In a training session, participants were presented with faces from two sets. In one set all faces were accompanied by characteristic auditory stimuli during learning (d-faces: different languages, intonations, accents, etc.). In the other set, all faces were accompanied by typical auditory stimuli during learning(s-faces: same words, same language). Face stimuli were counterbalanced across auditory conditions. We measured recognition performance in an old/new recognition task. Face recognition alone was tested. Our results show that participants were significantly better (t(12) = 3.89, p< 0.005) at recognizing d-faces than s-faces in the test session. These results show that there is an interaction between different sensory inputs and that typicality of stimuli in one modality can be modified by concomitantly presented stimuli in other sensory modalities. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/3/9/825.abstract Sarasota, FL, USA Third Annual Meeting of the Vision Sciences Society (VSS 2003) 10.1167/3.9.825 isaIBülthoff fionaFNNewell conference 2935 2003 9 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft Granada, Spain European Conference on Cognitive Psychology en KLander chuangLChuang VBruce conference 2934 2003 7 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft Perth, Australia 12th International Conference on Perception and Action KLander chuangLChuang poster 4692 2003 6 29 1017 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.neuroanatomie.uni-goettingen.de/neurobio_archiv/2003/pdf/proceedings2003.pdf Elsner, N. , H. Zimmermann Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Germany 29th Göttingen Neurobiology Conference en armannRArmann CSeelmann JSchramme poster 3191 Journal of Cognitive Neuroscience 2003 4 15 Supplement 189 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://cogneurosociety.org/annual-meeting/previous-meetings/2003_abstracts_edit.xls/view Biologische Kybernetik Max-Planck-Gesellschaft New York, NY, USA 10th Annual Meeting of the Cognitive Neuroscience Society johannesJSchultz KFriston DWolpert CDFrith poster BulthoffN2003 2003 2 6 147 Various factors have been identied that in uence face recognition. Despite the diversity of the studies on face recognition, mostly factors related to visual information have been investigated so far. Among factors like facial motion, orientation and illumination, the distinctiveness of faces has been extensively studied. It is well known that distinctive faces are more easily recognized than typical faces in memory tasks. In our study we have addressed the question whether factors that are not of visual nature might also in uence face recognition. More specically, our experimental question was: can visually typical faces become perceptually distinctive when they are accompanied by voice stimuli that are distinctive and can these faces therefore become in this way more easily recognizable? In a training session, participants saw faces from two sets. In one set all faces were accompanied by characteristic auditory stimuli during learning (d-faces: dierent languages, intonations, accents, etc.). In the other set, all faces were accompanied by typical auditory stimuli during learning(s-faces: same words, same language). Face stimuli were counterbalanced across auditory conditions. Face recognition alone was tested. We measured recognition performance in an old/new recognition task. Our results show that participants were signicantly better (t(12) = 3.89, p< 0.005) at recognizing d-faces than s-faces in the test session. Thus, our results demonstrate the perceptual quality of auditory stimuli (distinctive or typical) presented simultaneously with face stimuli can modify face recognition performance in a subsequent memory task and that typicality of stimuli in one modality can be modied by concomitantly presented stimuli in other sensory modalities. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk03/ Tübingen, Germany 6. Tübinger Wahrnehmungskonferenz (TWK 2003) isaIBülthoff FNNewell inbook 1132 2003 146-172 In this chapter we will review experiments using both explicit and implicit tasks to investigate object recognition using familiar objects (faces), unusual renderings of familiar objects (point-light walker), and novel scenes. While it is unlikely that participants would have already seen the particular renderings of familiar objects used in an experiment, they have definitely seen similar objects. For this reason, unfamiliar objects are used in many experiments to circumvent the problem of uncontrolled variations in prior exposure to objects. Another reason for using unfamiliar objects is that they allow us precise control over the types of features that are available for discrimination. How our visual system represents familiar and unfamiliar three-dimensional objects for the purpose of recognition is a difficult and passionately discussed issue. At the theoretical level a key question that any representational scheme has to address is how much the internal model depends on the viewing parameters. We will present 2 types of models regarding this issue and also address the question of whether the recognition process is more analytic or more holistic. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://psycnet.apa.org/psycinfo/2003-88086-006 Peterson, M.A. , G. Rhodes Oxford University Press

New York, NY, USA

Perception of Faces, Objects, and Scenes: Analytic and Holistic Processes Biologische Kybernetik Max-Planck-Gesellschaft 0-19-516538-1 isaIBülthoff hhbHHBülthoff poster Bulthoff2002 Journal of Vision 2002 11 2 7 620 Faces are easily categorized as male or female. But is this categorization done at the perceptual level? In previous studies (ECVP 2001), we found no categorical perception of gender for face stimuli using two discrimination tasks: either simultaneous same-different task or delayed matching-to-sample. This conflicts with results of another study using a different task (Campanella et al, Visual Cognition, 2001). Here we tested whether categorical perception of gender might become apparent if we used a discrimination task (sequential same-different task) more similar to that used by Campanella et al. We employed the same type of stimuli as in our previous experiments. The face stimuli were created by generating series of morphs between pairs of male and female 3D faces (gender continua). We also generated a gender continuum based on an average face. While gender-related information was present in this latter continuum, the stimuli lacked individual characteristic facial features that might induce identity-related categorical perception. If male and female faces belong to perceptually distinct gender categories, we would expect that two faces that straddle the gender boundary are more easily discriminated than two faces that belonged to the same gender category. In our previous experiments we never found any evidence of categorical perception for unfamiliar faces. Our present results confirm these findings. We found no evidence that participants could discriminate more easily between faces that straddle the gender category. Thus no categorical effect for face gender was revealed when sequential same-different discrimination task was used. The conflicting results obtained by both studies do not appear to be due to the different discrimination tasks employed. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.journalofvision.org/content/2/7/620.abstract Sarasota, FL, USA Second Annual Meeting of the Vision Sciences Society (VSS 2002) 10.1167/2.7.620 isaIBülthoff poster 3192 8th International Conference on Functional Mapping of the Human Brain (HBM 2003) 2002 6 8 14289 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.idac.tohoku.ac.jp/HBM2002/index.html Biologische Kybernetik Max-Planck-Gesellschaft johannesJSchultz JIngram DWolpert CFrith poster 1131 2002 2 5 84 In previous studies, we investigated whether male and female faces are perceived as distinct categories at the perceptual level and found no evidence of categorical perception using various discrimination tasks. In the present study we tested whether categorical perception of our stimuli might become apparent with yet another discrimination task, a sequential same-different task. The face stimuli used in all our experiments were derived from a database of 200 3D-laser scans of male and female faces (http://faces.kyb.tuebingen.mpg.de). Series of 3D-morphs were computed between individual male and female faces using the method of Blanz & Vetter (1999). Additionally, all faces of the database were used to compute average male and female faces to generate another series of morphs which was devoid of any individual features. One prediction of categorical perception is that two face stimuli that belong to different gender categories should be easier to discriminate than two face stimuli belonging to the same gender. In all our studies including the present one, most face pairs that straddle the gender category were not more easily discriminated than same category pairs. Thus, despite the use of different discrimination tasks, we found no categorical effect for face gender with our face stimuli, even when exemplar specific effects are eliminated as it is the case with average faces. We will discuss these results and compare them to the conflicting results of Campanella et al. (2001) who carried out similar experiments with different morphing techniques http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk02/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 5. Tübinger Wahrnehmungskonferenz (TWK 2002) isaIBülthoff poster 1111 2002 2 5 83 Caricatured faces are recognized as quickly and accurately as (and sometimes faster and better than) the veridical versions (Benson & Perrett, 1994). This “caricature effect” (CE) has been demonstrated only for the frontal view of faces and only when the caricatures were presented during the testing phase. First, we investigated whether the caricature effect generalizes across changes in viewpoint (frontal, three-quarter, and profile). Second, we examined the effect of presenting caricatured faces during the learning phase, which we term the “reverse caricature effect” (RCE). Face recognition performance was tested using two tasks: an old/new recognition paradigm and a sequential matching task. Observers learned faces either in the frontal, three-quarter, or profile views, and were tested with all three viewpoints. Half of the subjects participated in the CE condition (learning with veridicals, testing with caricatures) and the other half of the subjects participated in the RCE condition (learning with caricatures, testing with veridicals). The caricatures were created using a 3D face morphing algorithm (Blanz & Vetter, 1999). Accuracy sensitivity was measured using d’. For the CE condition, caricatures were recognized more accurately than veridical versions of the same face (mean d’: sequential matching: caricature=1.15, veridical=1.09; Old/New: caricature=1.42, veridical=1.18). This difference was (nearly) significant (sequential matching: F(2,58)=28, p<0.001; Old/ New: F(1, 162)=3.19, p=0.076). The interaction between face caricature level and viewpoint (testing view and/or learning view) was not significant. This suggests that the caricature effect generalizes across viewpoint. Similar results were found for the RCE condition. These results are discussed within the framework of a face space model for representing faces. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf1111.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk02/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 5. Tübinger Wahrnehmungskonferenz (TWK 2002) babsyBKnappmeyer CTappe isaIBülthoff poster 1133 Journal of Vision 2001 12 1 3 281 Background: Our visual system uses a sophisticated mechanism called categorical perception to discriminate between highly similar objects. Small perceptual differences are enhanced thus creating clear boundaries between groups of items. Purpose: Although it seems to be an easy task to classify people by gender, we wondered whether facial information was sufficient for this purpose. Using the morphing technique of Blanz and Vetter (1999) we built an average three-dimensional head model from a database of 200 laser-scanned faces. We constructed an artificial gender continuum of this average head and used the faces in categorization and discrimination experiments. Results: Gender information was present in our face set and was easily identified by the participants. However when we tested for the existence of a categorical effect, we found no evidence of enhanced discrimination for faces straddling the gender category boundary. In previous studies we found also no evidence of categorical perception when using faces of individuals (Buelthoff & Newell, 2000). Our results with average faces confirm the previous findings and avoid any personal distinctive features that might interfere with the analysis. Furthermore, the use of average faces insures to have endpoint faces situated at approximately equal distance from the gender boundary. Conclusion: The absence of a categorical effect is surprising. Categorical perception has been shown repeatedly for other information displayed by faces (expressions and identity). Although we can tell quite reliably the sex of a face, there is no evidence of a distorted perceptual space for face gender. Furthermore our results show that categorical perception does not always exist when similar items are categorized, not even for an important category like faces. Clearly, despite its enormous importance for social interactions we have not learned to deal with the gender of faces very effectively. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf1133.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://journalofvision.org/1/3/281 Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA First Annual Meeting of the Vision Sciences Society (VSS 2001) 10.1167/1.3.281 isaIBülthoff fionaFNNewell poster 1134 Perception 2001 8 30 ECVP Abstract Supplement 54 Categorical perception is a sophisticated mechanism which allows our visual system to discriminate between highly similar objects. Perceptually, physical differences between groups of objects are enhanced as compared to equal-sized differences within a group of objects, thus creating clear boundaries between groups of items. Humans are expert in face recognition. Does a categorical perception mechanism help us to differentiate between male and female faces? Using a three-dimensional morphing technique, we built an average. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v010045 Biologische Kybernetik Max-Planck-Gesellschaft Kusadasi, Turkey Twenty-fourth European Conference on Visual Perception isaIBülthoff fionaFNNewell poster 3193 NeuroImage 2001 6 13 6:Supplement S473 In law theory, an important distinction is made between legal reasoning and a natural, intuitive sense of justice. We designed a simple word-based experiment to investigate with fMRI whether the neural correlates of making law-based or justice-ba\cd decisions are different. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science?_ob=MiamiImageURL&_cid=272508&_user=29041&_pii=S1053811901918166&_check=y&_origin=search&_coverDate=30-Jun-2001&view=c&wchp=dGLbVlB-zSkzV&md5=1462545766370bd354ea0f91beaf5f3d/1-s2.0-S1053811901918166-main.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/S1053-8119(01)91816-6 johannesJSchultz ORGoodenough RFrackowiak CDFrith poster 1114 2000 11 8 5 The finding that caricatures are recognized more quickly and accurately than veridical faces has been demonstrated only for frontal views of human faces (e.g., Benson & Perrett, 1994). In the present study, we investigated whether there is also a “caricature effect” for three-quarter and profile views. Furthermore, we examined what happens to the caricature advantage when generalizing across view changes. We applied a 3D caricature algorithm to laser scanned head models. In a sequential matching task, we systematically varied the view of the target faces (left/right profile, left/right three-quarter, full-face), the view of the test faces (left/right profile, left/right threequarter, fullface) and the face type (anticaricature, veridical, caricature). The caricature effect was replicated for frontal views. We also found a clear caricature advantage for three-quarter and profile views. When generalizing across views, the caricature advantage was present for the majority of view change conditions. In a few conditions, there was an anticaricature advantage. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.opam.net/opam2000/OPAM_2000_Pro.pdf Biologische Kybernetik Max-Planck-Gesellschaft New Orleans, LA, USA 8th Annual Workshop on Object Perception and Memory (OPAM 2000) yichengCYCheng babsyBKnappmeyer isaIBülthoff poster 109 Perception 2000 8 29 ECVP Abstract Supplement 57 We could find no evidence for categorical perception of face gender using unfamiliar human faces (I Bülthoff et al, 1998 Perception 27 Supplement, 127a). Therefore we have investigated whether familiarising participants with the stimuli prior to testing might favour categorical perception. We created artificial gender continua using 3-D morphs between laser-scanned heads. The observers had to classify all faces according to their gender in a classification task. If perception of face gender is categorical, we would expect participants to classify the morphs into two distinct gender categories. Furthermore, they should differentiate pairs of morphs that straddle the gender boundary more accurately than other pairs in a discrimination task. The participants were familiarised before testing with half of the faces used for creating the morphs. They could categorise most familiar and unfamiliar faces into distinctive gender categories. Thus, they could extract the gender information and use it to classify the images. On the other hand, we found no evidence of increased discriminability for the morph pairs that straddle the gender boundary. Apparently, observers did not perceive the gender of a face categorically, even when these faces were familiar to them. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf109.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v000177 Biologische Kybernetik Max-Planck-Gesellschaft Groningen, Netherlands 23rd European Conference on Visual Perception (ECVP 2000) isaIBülthoff fionaFNNewell poster 110 Investigative Ophthalmology & Visual Science 2000 5 41 4 S225 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf110.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Fort Lauderdale, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 2000) isaIBülthoff fionaFNNewell poster 287 1999 2 52 Zeigt die Bestimmung der Geschlechtszugehörigkeit von Gesichtern die charakteristischen Merkmale der kategorischen Wahrnehmung? Durch ein automatisiertes 3D-Morph-Verfahren wurden aus 3D-Laser-scans von männlichen und weiblichen Köpfen Misch-Gesichter synthetisiert. Das Morph-Verfahren erlaubt sowohl die Textur als auch die Form eines Gesichtes zu verändern, so daß Pigmentation und Form zwischen männlichen und weiblichen Gesichtern kontinuierlich angepaßt werden können. Andere geschlechtsspezifische Merkmale wie Frisur, Bart, Make-up oder Schmuck wurden weggelassen oder computergraphisch entfernt. Alle Gesichter wurden in frontaler oder seitlicher Ansicht (3/4-view) mit neutralem Gesichtsausdruck präsentiert. Versuchspersonen haben zuerst eine Diskriminationsaufgabe (XAB-Test) durchgeführt und danach wurde die subjektive Geschlechtsgrenze entlang des Morph-Kontinuums in einer Kategorisierungsaufgabe bestimmt. Es zeigte sich für alle Versuchspersonen die typische Stufenfunktion in der Kategorisierungsaufgabe. Im XAB-Test war es jedoch für die Versuchspersonen nicht einfacher, ein Gesichtspaar zu unterscheiden, das durch die putative kategorische Geschlechtsgrenze getrennt war als für Gesichtspaare an dem mehr weiblichen oder männlichen Ende des Morph-Kontinuums. Unsere Experimente zeigen, daß das Geschlecht eines Gesichts nicht kategorisch wahrgenommen wird. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf287.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk99/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 2. Tübinger Wahrnehmungskonferenz (TWK 99) isaIBülthoff fionaFNNewell vetterTVetter article 184 Spatial Vision 1999 1 12 1 107-123 To explore the nature of the representation space of 3D objects, we studied human performance in forced-choice categorization of objects composed of four geon-like parts emanating from a common center. Two categories were defined by prototypical objects, distinguished by qualitative properties of their parts (bulging vs waist-like limbs). Subjects were trained to discriminate between the two prototypes (shown briefly, from a number of viewpoints, in stereo) in a 1-interval forced-choice task, until they reached a 90% correct-response performance level. After training, in the first experiment, 11 subjects were tested on shapes obtained by varying the prototypical parameters both orthogonally (ORTHO) and in parallel (PARA) to the line connecting the prototypes in the parameter space. For the eight subjects who performed above chance, the error rate increased with the ORTHO parameter-space displacement between the stimulus and the corresponding prototype; the effect of the PARA displacement was weaker. Thus, the parameter-space location of the stimuli mattered more than the qualitative contrasts, which were always present. To find out whether both prototypes or just the nearest one to the test shape influenced the decision, in the second experiment we varied the similarity between the categories. Specifically, in the test stage trials the distance between the two prototypes could assume one of three values (FAR, INTERMEDIATE, and NEAR). For the 13 subjects who performed above chance, the error rate (on physically identical stimuli) in the NEAR condition was higher than in the other two conditions. The results of the two experiments contradict the prediction of theories that postulate exclusive reliance on qualitative contrasts, and support the notion of a representation space in which distances to more than one reference point or prototype are encoded (Edelman, 1998). http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf184.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.ingentaconnect.com/search/download?pub=infobike%3a%2f%2fvsp%2fspv%2f1999%2f00000012%2f00000001%2fart00006&mimetype=application%2fpdf&exitTargetId=1309268380820 Biologische Kybernetik Max-Planck-Gesellschaft 10.1163/156856899X00067 SEdelman hhbHHBülthoff isaIBülthoff poster 3194 Translation and Stability of mRNA Meeting at the Palo Alto Institute of Molecular Medicine 1999 1999 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft johannesJSchultz RBoeck PLinder inproceedings 251 1998 8 314-319 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Grondin, S. , Y. Lacouture Université Laval

Quebec, Canada

Fechner Day 98 Biologische Kybernetik Max-Planck-Gesellschaft Quebec, Canada Fourteenth Annual Meeting of the International Society for Psychophysics MAPavlova ANSokolov isaIBülthoff poster BulthoffNVB1998 Perception 1998 8 27 ECVP Abstract Supplement 127 We investigated whether the judgment of face gender shows the typical characteristics of categorical perception. As stimuli we used images of morphs created between pairs of male/female 3-D head laser scans. In experiment 1, texture and shape were morphed between both faces. In experiment 2, either the average texture of all faces was mapped onto the shape continuum between the two faces or we mapped the texture continuum between each face pair onto an average shape face. Thus, either the shape or the texture remained constant in any one condition. The subjects viewed these morphs first in a discrimination task (XAB) and then in a categorisation task which was used to locate the subjective gender boundary between each male/female face pair. Although we found that subjects could categorise the face images by their gender in the categorisation task and that texture alone is a better gender indicator than shape alone, the subjects did not discriminate more easily between face images situated at the category boundary in any of our discrimination experiments. We argue that we do not perceive the gender of a face categorically and that more cues are needed to decide the gender of a person than those provided by the faces only. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v980543 Oxford, UK 21st European Conference on Visual Perception isaIBülthoff fionaFNNewell vetterTVetter hhbHHBülthoff poster 1123 Perception 1998 8 27 ECVP Abstract Supplement 127 We investigated whether the judgment of face gender shows the typical characteristics of categorical perception. As stimuli we used images of morphs created between pairs of male/female 3-D head laser scans. In experiment 1, texture and shape were morphed between both faces. In experiment 2, either the average texture of all faces was mapped onto the shape continuum between the two faces or we mapped the texture continuum between each face pair onto an average shape face. Thus, either the shape or the texture remained constant in any one condition. The subjects viewed these morphs first in a discrimination task (XAB) and then in a categorisation task which was used to locate the subjective gender boundary between each male/female face pair. Although we found that subjects could categorise the face images by their gender in the categorisation task and that texture alone is a better gender indicator than shape alone, the subjects did not discriminate more easily between face images situated at the category boundary in any of our discrimination experiments. We argue that we do not perceive the gender of a face categorically and that more cues are needed to decide the gender of a person than those provided by the faces only. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v980543 Biologische Kybernetik Max-Planck-Gesellschaft Oxford, UK 21st European Conference on Visual Perception isaIBülthoff fionaFNNewell vetterTVetter hhbHHBülthoff poster 1065 Perception 1998 8 27 ECVP Abstract Supplement 123 Recently, we showed that recovery of a priori known structure from biological motion leveled off with changing display orientation (eg Pavlova and Sokolov, 1997 Perception 26 Supplement, 92). How does image-plane rotation of a prime affect detection of a camouflaged point-light walker? At each of five randomly presented display orientations between upright and inverted (0°, 45°, 90°, 135°, and 180°), viewers saw a sequence of displays (each display for 1 s). Half of them comprised a camouflaged point-light walker, and half a 'scrambled-walker' mask. In a confidence-rating procedure, observers judged whether a walker was present. Prior to each experimental sequence, they were primed (for 10 s) either with an upright-, 45°-, 90°-, or 180°-oriented sample of the walker. Pronounced priming effects were found only with an upright-oriented prime: it improved detectability for the same-oriented displays, and to a lesser extent for 45°. With 45°-prime, sensitivity for 0°-, 45°-, and 90°-oriented displays was higher than for 135° and 180°. However, with 90°- and 180°-primes ROC curves for all orientations were situated close to one another. These findings indicate that the priming effect in biological motion is partly independent of the relative orientation of priming and primed displays. Moreover, it occurs only if a prime corresponds to a limited range of deviations from upright orientation within which display is spontaneously recognisable despite a discrepancy between event kinematics and dynamics (Pavlova, 1996 Perception 25 Supplement, 6). The primacy of dynamic constraints in the perception of structure from biological motion is discussed. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.perceptionweb.com/abstract.cgi?id=v980506 Biologische Kybernetik Max-Planck-Gesellschaft Oxford, UK 21st European Conference on Visual Perception MAPavlova isaIBülthoff ANSokolov article 148 Nature Neuroscience 1998 7 1 3 254-257 The interaction between depth perception and object recognition has important implications for the nature of mental object representations and models of hierarchical organization of visual processing. It is often believed that the computation of depth influences subsequent high-level object recognition processes, and that depth processing is an early vision task that is largely immune to 'top-down' object-specific influences, such as object recognition. Here we present experimental evidence that challenges both these assumptions in the specific context of stereoscopic depth-perception. We have found that observers' recognition of familiar dynamic three- dimensional (3D) objects is unaffected even when the objects' depth structure is scrambled, as long as their two-dimensional (2D) projections are unchanged. Furthermore, the observers seem perceptually unaware of the depth anomalies introduced by scrambling. We attribute the latter result to a top-down recognition-based influence whereby expectations about a familiar object's 3D structure override the true stereoscopic information. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf148.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.nature.com/neuro/journal/v1/n3/pdf/nn0798_254.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1038/699 isaIBülthoff hhbHHBülthoff pawanPSinha inproceedings 344 1998 7 64-68 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff B. Bril, A. Ledebt, G. Dietrich , A. Roby-Brami Editions EDK

Paris, France

Advances in Perception-Action Coupling Biologische Kybernetik Max-Planck-Gesellschaft Pont-à-Mousson, France Fifth European Workshop on Ecological Psychology (EWEP 5) MAPavlova ANSokolov isaIBülthoff poster 1125 Investigative Ophthalmology & Visual Science 1998 5 39 4 173 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Fort Lauderdale, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 1998) fionaFNNewell isaIBülthoff vetterTVetter hhbHHBülthoff poster 1124 Investigative Ophthalmology & Visual Science 1998 5 39 4 171 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Fort Lauderdale, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 1998) isaIBülthoff fionaFNNewell vetterTVetter hhbHHBülthoff poster 283 1998 2 120 In spite of potential perceptual ambiguity of a point-light walking figure, with upright display orientation observers can readily recover the invariant structure from biological motion. However, regardless of the same low-level relations between moving dots within upright and inverted orientation, perception of a point-light walker is dramatically impeded with 180º-display inversion. Spontaneous recognition was found to improve abruptly with changing display orientation from inverted to upright (Pavlova, 1996, Perception 25, Suppl.). This evidence implies that the visual system implements additional processing constraints for the unambiguous interpretation of biological motion. We used a masking paradigm to study the processing constraints in biological motion perception. At each of randomly presented five orientations (0°, 45°, 90°, 135°, and 180°), viewers saw a sequence of 210 displays. Half of them comprised a canonical 11 pointlight walker, and half a partly distorted walker, in which rigid pair-wise connections between moving dots were perturbed. A 66-dot “scrambled-walker” mask camouflaged both figures. Prior each experimental sequence, a sample of a canonical walker in respective orientation was demonstrated. Observers judged whether a canonical figure was present. A jackknife estimating of the ROC parameters indicated that detectability leveled off with changing orientation from upright to 135°, and then slightly increased to display inversion. However, even with 135° and 180° it was above chance. For orientations 0°, 45° and 90°, perceptual learning to detect a canonical walker proceeded rather rapidly in the course of the experiment. Comparison with the data on spontaneous recognition of biological motion suggests that display orientation affects bottom-up processing of biological motion more strongly than top-down. We suppose that some processing constraints (such as axis-of-symmetry, dynamic constraints) in perception of biological motion be hierarchically nested. Dynamic constraints appear to be the most powerful: the highest detectability was found with upright orientation. While with changing orientation these constraints lose their strength, others processing constraints are getting more influential. For instance, the lower sensitivity for 135° as compared to 180° might be accounted for by the axis-of-symmetry constraint that is implemented by the visual system at 180°. Likewise, due to the inefficiency of this constraint, biological motion pattern is perceived as more multistable with 90°-150°, as compared to 180° display orientation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.twk.tuebingen.mpg.de/twk98/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 1. Tübinger Wahrnehmungskonferenz (TWK 98) MAPavlova ANSokolov isaIBülthoff techreport 1512 1997 2 47 Much of the experimental and computational modeling research on human recognition processes has focused exclusively on the domain of static three-dimensional (3D) objects. The issue of the nature of internal representations underlying dynamic 3D object recognition is largely unexplored. Here we examine this issue, with emphasis on view-point dependency, using variants of biological motion sequences of the kind described by Johansson (1973). Our first experiment investigated whether observers exhibit the well-known canonical view-point effect while recognizing 3D biological motion sequences. Results showing a markedly impaired recognition performance with sequences recorded from unusual view-points provide preliminary evidence for the role of view-point familiarity and the inability of the visual system to extract view-independent representations. Next, to examine whether the motion traces used for recognition preserve 3D information, or are largely 2D, we developed a special class of biological motion sequences. The distinguishing characteristic of these sequences was that while they preserve the `normal' 2D projections from one view-point, their 3D structures were randomized. View-points preserving the `normal' 2D projections yielded vivid biological motion percepts, whereas other viewpoints yielded percepts of randomly moving dots. In the final set of experiments we examined whether this result could be an outcome of a recognition-dependent top-down suppression of anomalies in 3D structures. Our results indicate that subjects' expectations about 3D structure can suppress the bottom-up depth information provided by binocular stereo. Taken together, these findings suggest that biological motion sequences are represented by the human visual system as 2D traces rather than as 3D structural descriptions, and that the perception of 3D structure may be based not only upon low-level processes but also upon recognition-dependent top-down influences. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics, Tübingen, Germany isaIBülthoff hhbHHBülthoff pawanPSinha techreport 1504 1996 9 40 To explore the nature of the representation space of 3D objects, we studied human performance in forced-choice classification of objects composed of four geon-like parts, emanating from a common center. The two class prototypes were distinguished by qualitative contrasts (bulging vs.\ waist-like limbs). Subjects were trained to discriminate between the two prototypes (shown briefly, from a number of viewpoints, in stereo) in a 1-interval forced-choice task, until they reached a 90% correct-response performance level. In the first experiment, 11 subjects were tested on shapes obtained by varying the prototypical parameters both orthogonally (Ortho) and in parallel (Para) to the line connecting the prototypes in the parameter space. For the eight subjects who performed above chance, the error rate increased with the Ortho parameter-space displacement between the stimulus and the corresponding prototype (the effect of the Para displacement was marginal). Clearly, the parameter-space location of the stimuli mattered more than the qualitative contrasts (which were always present). To find out whether both prototypes or just the nearest neighbor of the test shape influenced the decision, in the second experiment we tested 18 new subjects on a fixed set of shapes, while the test-stage distance between the two classes assumed one of three values (Far, Intermediate, and Near). For the 13 subjects who performed above chance, the error rate (on physically identical stimuli) in the Near condition was higher than in the other two conditions. The results of the two experiments contradict the prediction of theories that postulate exclusive reliance on qualitative contrasts, and support the notion of a metric representation space, with the subjects' performance determined by distances to more than one reference point or prototype. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf1504.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institute for Biological Cybernetics, Tübingen, Germany edelmanSEdelman hhbHHBülthoff isaIBülthoff conference 1121 Perception 1996 9 25 ECVP Abstract Supplement 49-50 To explore the nature of the representation space of 3-D objects, we studied human performance in forced-choice classification of objects composed of four geon-like parts, emanating from a common centre. The two class prototypes were distinguished by qualitative contrasts (cross-section shape; bulge/waist), and by metric parameters (degree of bulge/waist, taper ratio). Subjects were trained to discriminate between the two prototypes (shown briefly, from a number of viewpoints, in stereo) in a 1-interval forced-choice task, until they reached a 90% correct-response performance level. In experiment 1, eleven subjects were tested on shapes obtained by varying the prototypical parameters both orthogonally (Ortho), and in parallel (Para) to the line connecting the prototypes in the parameter space. For the eight subjects who performed above chance, the error rate increased with the Ortho parameter-space displacement between the stimulus and the corresponding prototype: F1,68=3.6, p<0.06 (the effect of the Para displacement was marginal). Clearly, the parameter-space location of the stimuli mattered more than the qualitative contrasts (which were always present). To find out whether both prototypes or just the nearest neighbour of the test shape influenced the decision, in experiment 2 eight new subjects were tested on a fixed set of shapes, while the test-stage distance between the two classes assumed one of three values (Far, Intermediate, or Near). For the six subjects who performed above chance, the error rate (on physically identical stimuli) in the Near condition was higher than in the other two conditions: F1,89=3.7, p<0.06. The results of the two experiments contradict the prediction of theories that postulate exclusive reliance on qualitative contrasts, and support the notion of a metric representation space with the subjects' performance determined by distances to more than one reference point or prototype (cf Edelman, 1995 Minds and Machines 5 45 - 68). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Abstract Talk http://www.perceptionweb.com/abstract.cgi?id=v96l1105 Biologische Kybernetik Max-Planck-Gesellschaft Strasbourg, France 19th European Conference of Visual Perception hhbHHBülthoff SEdelman isaIBülthoff poster 568 Investigative Ophthalmology & Visual Science 1996 4 37 3 1125 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Fort Lauderdale, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology SEdelman hhbHHBülthoff isaIBülthoff poster 566 Investigative Ophthalmology & Visual Science 1996 4 37 3 1125 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Fort Lauderdale, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 1996) isaIBülthoff pawanPSinha hhbHHBülthoff article 576 Nature 1996 1 379 6560 31-31 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff http://www.nature.com/nature/journal/v379/n6560/pdf/379031a0.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1038/379031a0 kerstenDKersten DCKnill pascalPMamassian isaIBülthoff poster 1120 Perception 1995 8 24 ECVP Abstract Supplement 112 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 18th European Conference on Visual Perception isaIBülthoff pawanPSinha poster 1122 Investigative Ophthalmology & Visual Sciences 1995 5 36 4 S417 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Fort Lauderdale, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 1995) pawanPSinha hhbHHBülthoff isaIBülthoff poster 680 Investigative Ophthalmology & Visual Science 1994 5 35 4 1741 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Bülthoff Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 1994) isaIBülthoff kerstenDKersten hhbHHBülthoff poster 3195 Annual Meeting of the Swiss Societies for Experimental Biology (USGEB) 1994 3 1994 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft johannesJSchultz J-PHornung article 833 Brain Research 1987 3 407 1 152-158 Movement detection is one of the most elementary visual computations performed by vertebrates as well as invertebrates. However, comparatively little is known about the biophysical mechanisms underlying this computation. It has been proposed on both physiological1.8.21 and theoretical2.15.23 grounds that inhibition plays a crucial role in the directional selectivity of elementary movement detectors (EMDs). For the first time, we have studied electrophysiological and behavioral changes induced in flies after application of picrotoxinin, an antagonist of GABA. The results show that inhibitory interactions play an important role in movement detection in flies. Furthermore, our behavioral results suggest that the computation of object position is based primarily on movement detection. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf833.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6SYR-485RK87-1R-1&_cdi=4841&_user=29041&_pii=0006899387912303&_origin=&_coverDate=03%2F24%2F1987&_sk=995929998&view=c&wchp=dGLzVzz-zSkzS&md5=d8090eb575009f2a056c984b1b95a05d&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/0006-8993(87)91230-3 hhbHHBülthoff isaIBülthoff article 823 Biological Cybernetics 1987 2 55 5 313-320 The optomotor following response, a behavior based on movement detection was recorded in the fruitflyDrosophila melanogaster before and after the injection of picrotoxinin, an antagonist of the inhibitory neurotransmitter GABA. The directional selectivity of this response was transiently abolished or inverted after injection. This result is in agreement with picrotoxinin-induced modifications observed in electrophysiological activity of direction-selective cells in flies (Bülthoff and Schmid 1983; Schmid and Bülthoff, in preparation). Furthermore, walking and flying flies treated with picrotoxinin followed more actively motion from back to front instead of front to back as in normal animals. Since the difference in the responses to front to back and back to front motions is proposed to be the basis of fixation behavior in flies (Reichardt 1973) our results support this notion and are inconsistent with schemes explaining fixation by alternative mechanisms. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/combining_neuropharmacology_and_behavior_to_study_motion_detection_in_flies_823[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.springerlink.com/content/y056t6h64564n574/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF02281977 hhbHHBülthoff isaIBülthoff article 1128 Journal of Comparative Physiology 1986 158 195-202 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Emeriti Biologische Kybernetik Max-Planck-Gesellschaft isaIBülthoff article 1129 Journal of Neuroscience Methods 1985 5 13 3-4 183-190 High resolution of [3H]2-deoxyglucose labelling was obtained in autoradiographs of Drosophila brains after freeze-substitution in anhydrous acetone at −76°C. This method was applied to preparations which received visual, olfactory and mechanosensory stimulation. The autoradiographs were compared to those obtained after freeze-drying. Freeze-substitution, which has proved to be technically simple, rapid and inexpensive, yields a good quality of tissue preservation and hence is recommended for tissue dehydration prior to autoradiography. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.sciencedirect.com/science/article/pii/0165027085900664 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/0165-0270(85)90066-4 VRodrigues isaIBülthoff poster 837 Investigative Ophthalmology & Visual Science 1985 5 26 3 56 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft Sarasota, FL, USA Annual Spring Meeting of the Association for Research in Vision and Ophthalmology (ARVO 1985) hhbHHBülthoff isaIBülthoff poster 844 Verhandlungen der Deutschen Zoologischen Gesellschaft 1985 5 78 223 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/umkehrung_der_bewegungs_und_objektwahrnehmung_durch_einen_gaba_antagonisten_bei_fliegen_844[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft Wien, Austria 78. Jahresversammlung der Deutschen Zoologischen Gesellschaft hhbHHBülthoff isaIBülthoff article 1127 Journal of Comparative Physiology 1985 156 25-34 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Emeriti Biologische Kybernetik Max-Planck-Gesellschaft isaIBülthoff EBuchner poster 840 Verhandlungen der Deutschen Zoologischen Gesellschaft 1984 6 77 276 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/beeinflussung_der_bewegungsdetektion_durch_neuropharmaka_840[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft Giessen, Germany 77. Jahresversammlung der Deutschen Zoologischen Gesellschaft hhbHHBülthoff isaIBülthoff ASchmid article 1126 Journal of Comparative Physiology 1984 155 471-483 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Emeriti Biologische Kybernetik Max-Planck-Gesellschaft EBuchner SBuchner isaIBülthoff