3369 3 JD Restat SD Steck HF Mochnatzki HP Mallot 2004-06-00 6 33 667 687 Perception Theoretical considerations and earlier experimental findings indicate that traveling over slanted terrain can lead to an enrichment of the perceived spatial cues relevant for navigation. We investigated the proposed facilitation of a uniformly slanted environment on navigation and orientation performance with a virtual environment presented on a large 180° screen, using as material a virtual town with eight places and twenty-four landmarks. In the control condition, this town was placed on a flat surface; in the two experimental conditions, the town was placed on a slope with a uniform angle of 4°. Pedaling on a bicycle simulator, participants first explored the environment, then solved navigation tasks, pointed from various positions to distant landmarks, judged the relative elevation of pairs of distant landmarks from memory, and finally drew a sketch map of the environment. In comparison to the control condition, the number of navigation errors was significantly lower in the slanted conditions, and the deviations in the pointings to distant landmarks were massively reduced. Participants from the slant conditions also showed good knowledge of the relative elevations of pairs of distant locations. However, no differences in map-drawing quality were found. The results lend additional support to the proposition that our spatial knowledge, which is used in navigation and orientation, contains vertical information. no notspecified http://www.kyb.tuebingen.mpg.de/ published 20 15017 15422 102 3 SD Steck HA Mallot 2000-02-00 1 9 69 83 Presence: Teleoperators and Virtual Environments In visual navigation, landmarks can be used in a number of different ways. In this paper, we investigate the role of global and local landmarks in virtual environment navigation. We performed an experiment in a virtual environment called “Hexatown”, consisting of a regular hexagonal grid of streets and junctions. Each junction was identified by the presence of distinct local landmarks (buildings, phone box, and so on). Additionally, compass information or a global frame of reference was provided by global landmarks (hilltop, television tower, and city skyline). According to participants' movement decisions, egomotion was simulated, and displayed on a 180 deg. projection screen. Participants learned the route back and forth between two local landmarks. In the test phase, individual junctions were approached and the participant's movement decision was recorded. We performed two experiments involving landmark changes after learning. In the first, we used conflicting cues by transposing landmarks. In the second experiment, we reduced either local or global landmark information. Results show that both local and global landmarks are used in wayfinding decisions. However, different participants rely on different strategies. In the first experiment (cue conflict) for example, some of the participants used only local landmarks while others relied exclusively on global landmarks. Other participants used local landmarks at one location and global landmarks at the other. When removing one landmark type in the second experiment, the other type could be used by almost all participants, indicating that information about the neglected landmark type was present in memory. no notspecified http://www.kyb.tuebingen.mpg.de//fileadmin/user_upload/files/publications/pdf102.pdf published 14 15017 15422 206 7 HA Mallot S Gillner SD Steck MO Franz Stade, Germany1999-08-00 367 380 International Conference on Spatial Information Theory: Cognitive and Computational Foundations of Geographic Information Science (COSIT '99) The simplest representation of space allowing for spatial cognition in biological and artificial systems is a graph; the nodes of this graph contain local position information (views) chracterizing certain places while its links are labeled with movements or actions leading from one view to the next. In this paper, we review recent theoretical and psychological 2ork on view-graph representations. In particular, we will focus on the transition from stereotyped "recognition-triggered responses" to a graph-like cognitive map where the recognition of a view allows to choose one of several responses. We will present psychophysical evidence from experiments using virtual reality indicating that human subjects do make use of simple view-movement associations without recognizing places. This mechanism is not restricted to navigation in mazes but can be extended to large-scale open environments by means of an additional guidance mechanism. As compared to more map-like approaches such as occupancy grids or survey-maps, the view-graph is less computationally expensive and can easily be adapted to the coarseness of spatial knowledge. no notspecified http://www.kyb.tuebingen.mpg.de/ published 13 15017 15422 2382 2 SD Steck HF Mochnatzki HA Mallot Springer Berlin, Germany 2003-00-00 62 76 Spatial Cognition III: Routes and Navigation, Human Memory and Learning, Spatial Representation and Spatial Learning We investigatedthe role of geographical slant in simple navigation andspatial memory tasks, using an outdoor virtual environment. The whole environment couldb e slantedb y an angle of 4◦. Subjects could interact with the virtual environment by pedaling with force-feedback on a bicycle simulator (translation) or by hitting buttons (discrete rotations in 60◦ steps). After memory acquisition, spatial knowledge was accessed by three tasks: (i) pointing from various positions to the learnedgoals; (ii) choosing the more elevatedof two landmarks from memory; (iii) drawing a sketch map of the environment. The number of navigation errors (wrong motion decisions with respect to the goal) was significantly reducedin the slantedcond itions. Furthermore, we foundthat subjects were able to point to currently invisible targets in virtual environments. Adding a geographical slant improves this performance. We conclude that geographical slant plays a role either in the construction of a spatial memory, or in its readout, or in both. no notspecified http://www.kyb.tuebingen.mpg.de/ published 14 15017 15422 1549 46 SD Steck HF Mochnatzki HA Mallot 2001-01-00 2001-01-00 The Role of Geographical Slant in Virtual Environment Navigation no notspecified 15017 15422 1531 46 SD Steck HA Mallot 1998-10-00 1998-10-00 The Role of Global and Local Landmarks in Virtual Environment Navigation no notspecified 15017 15422 128 7 HA Mallot HF Mochnatzki SD Steck Fort Lauderdale, FL, USA2000-05-00 S228 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 2000) no notspecified http://www.kyb.tuebingen.mpg.de//fileadmin/user_upload/files/publications/pdf128.pdf published 0 15017 15422 139 7 SD Steck HA Mallot Fort Lauderdale, FL, USA2000-05-00 S224 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 2000) no notspecified http://www.kyb.tuebingen.mpg.de//fileadmin/user_upload/files/publications/pdf139.pdf published 0 15017 15422 129 7 HA Mallot SD Steck Tübingen, Germany2000-02-00 138 3. Tübinger Wahrnehmungskonferenz (TWK 2000) den nur Orte und ihre Nachbarschaften gespeichert (Konfigurationswissen), im zweiten Fall auch Koordinaten für alle bekannten Orte. Metrische Information kann aus der Eigenbewegungsschätzung oder der Tiefenwahrnehmung stammen, oder aufgrund der Konfiguration erschlossen werden (metrische Einbettung, multidimensionale Skalierung). Wir haben nun die Frage untersucht, ob metrische Informationen, die nicht direkt aus der Eigenbewegung stammt, in eine metrische Karte aufgenommen wird. Wird die metrische Repräsentation der Umgebung besser, wenn das Konfigurationswissen über eine Umgebung durch Hinzufügen einer zentralen Landmarke verbessert wird? Die Navigation wurde in einer virtuellen Umgebung durchgeführt, wobei visuelle und proprioceptive Reize simuliert wurden. Die Umgebung bestand aus drei partiell überlappenden Schleifen, die sich an einem zentralen Platz mit einem Glockenturm als zentraler Landmarke markiert. Wir verwendeten drei Verknüpfungsbedingungen. Fehlend: der zentrale Platz und die Landmarke wurden entfernt, so daß die drei Schleifen zu einer verschmolzen. Die Straßen von dieser Schleife in Richtung auf den zentralen Platz wurden zu Sackgassen. Sichtbar: Die zentrale Landmarke wurde eingefügt und war vom äußeren Ring aus sichtbar, aber nicht erreichbar. Erreichbar: Die Sackgassen wurden geöffnet. Nach einer Explorationsphase wurden 48 Versuchspersonen aufgefordert, 28 Abkürzungen zwischen vorher gelernten Orten zu navigieren. Dazu stellten sie zunächst die Richtung zum nicht aktuell sichtbaren Ziel ein. Dannach wurden alle Landmarken und Strassen aus der Simulation entfernt, und die Versuchspersonen bewegten sich geradeaus in die vorher eingestellte Richtung, bis sie glaubten, das Ziel erreicht zu haben. Wir verwendeten 14 zentraleWege (kürzeste Strassenverbindung führt über das Zentrum) und 14 periphere Wege. Navigationsfehler wurden als Abstand des Endpunktes eines Weges vom Ziel gemessen. Für die zentralen Wege waren die Fehler in der Bedingung "erreichbar" signifikant kleiner als in den anderen Bedingungen. Dies lässt darauf schliessen, dass die metrische Information, die beim Überqueren des Zentrums gewonnen wurde, genutzt wurde. Die Leistungen in der Bedingung "sichtbar" unterscheiden sich nicht von denen in Bedingung "fehlend", wohl aber von der Bedingung "erreichbar". Dies Bedeutet, daß die bloße Betrachtung der zentralen Landmarke, die dadurch in das Konfigurationswissen eingebaut werden konnte, nicht zu einer Verbesserung der metrischen Leistung führt. In der beschriebenen Aufgabe wurde die Leistung für metrische Aufgaben duch das Hinzufügen neuer Konfigurationsinformation nicht verbessert. Wir schliessen daraus, dass metrische Information nur verwendet wird, wenn sie aus der Eigenbewegung stammt, nicht aber wenn sie aus der Tiefenwahrnehmung stammt oder aus der Konfiguration erschlossen wird. no notspecified http://www.kyb.tuebingen.mpg.de//fileadmin/user_upload/files/publications/pdf129.pdf published -138 15017 15422 320 7 SD Steck HA Mallot Hanover, NH, USA1999-04-00 76 77 6th Annual Meeting of the Cognitive Neuroscience Society We investigated the role of global and local landmarks in the navigation of the `Hexatown' virtual environment (Gillner & Mallot, 1998, Journal of Cognitive Neuroscience). Hexatown consists of a regular hexagonal grid of streets and junctions. Each junction was identified by the presence of distinct `local landmarks' (buildings, phone box, etc.). Additionally, global direction or compass information was provided by `global landmarks' (hilltop, television tower, and city skyline). According to subjects' movement-decisions, egomotion was simulated, and displayed on a 180-degree-projection screen. Subjects learned the route back-and-forth between two local landmarks. In the test-phase individual junctions were approached and the subject's movement-decision was recorded. We performed two experiments involving landmark changes after learning: In the first, we used conflicting cues by transposing landmarks. In the second experiment we reduced either local or global landmark information. Results show that both local and global landmarks are used in way-finding decisions. However, different subjects rely on different strategies. In the first experiment (cue conflict) for example, some of the subjects used only local landmarks while others relied exclusively on global landmarks. There were also subjects who used local landmarks at one location and global landmarks at the other. When removing one landmark type in the second experiment, the other type could be used by almost all subjects indicating that information about the neglected landmark type was present in memory. no notspecified http://www.kyb.tuebingen.mpg.de//fileadmin/user_upload/files/publications/pdf320.pdf published 1 15017 15422 307 7 HF Mochnatzki SD Steck HA Mallot Tübingen, Germany1999-02-00 86 2. Tübinger Wahrnehmungskonferenz (TWK 99) known to make extensive use of geographical slant for communication about spatial layout (Brown and Levinson, Journal of Linguistic Anthropology 3: 46-74, 1993). We have investigated the role of geographic slant in a simple spatial memory task. The experimental environment is a modified version of the Hexatown virtual environment described by Gillner and Mallot (Journal of Cognitive Neuroscience 10: 445-463, 1998). This environment is a hexagonal grid of streets with landmarks placed in each angle between two streets. We used a version with 8 places and no loops. The whole environment could be slanted by an angle of 4 degrees. Three slant conditions were used: “flat”: no slant; “slanted NW”: slant direction 30 degrees north west with respect to some arbitrarily chosen “north”; slanted NE: slant direction 30 degrees north east. Subjects could interact with the virtual environment by pedaling with force-feedback on a bicycle simulator (translation) or by hitting buttons (discrete rotations in 60 degree steps). The environment was simulated using a Silicon Graphics ONYX2 computer. Images were projected on a 180 degree screen. For details of the setup, see van Veen et al. (Future Generation Computer Systems 14: 231-242, 1998). Subjects explored the environment by searching 15 routes to various goals presented to them as pictures. After learning, spatial memory was accessed by a pointing task: In an across subjects design, 3 groups of 6 subjects were asked to point from various positions to the learnt goals (19 pointings per subject). Overall performance is rather good, with a mean angular error of -5.9 degrees (plus/ minus 53 degrees mean angular deviation) in the “flat” condition. Performance was significantly better in both the “slanted NW” condition (circular F-test, p<0.00001) and the “slanted NE” condition (p<0.04). There is also a significant difference between the two slanted conditions (p < 0.01). The results show that subjects are able to point to currently invisible targets in virtual environments. Adding a geographic slant improves this performance. We conclude that geographical slant plays a role either in the construction of a spatial memory, or in its readout, or in both. no notspecified http://www.kyb.tuebingen.mpg.de//fileadmin/user_upload/files/publications/pdf307.pdf published -86 15017 15422 321 7 SD Steck HA Mallot Tübingen, Germany1999-02-00 82 2. Tübinger Wahrnehmungskonferenz (TWK 99) Wir untersuchten die Rolle lokaler und globaler Landmarken bei der Navigation in der virtuellen Umgebung "Hexatown" (Gillner & Mallot, 1998). Hexatown besteht aus einem regelmäßigen hexagonalen Grundriß aus Straßen und Kreuzungen. Jede Kreuzung besteht aus drei verschiedenen "lokalen Landmarken" (Gebäude, Telefonhäuschen, usw.). Zusätzliche globale Richtungen oder Kompaßinformation wurden durch "globale Landmarken" (Bergspitze, Fernsehturm, und die Silhouette einer entfernten Stadt) dargeboten. Die Eigenbewegung wurde entsprechend der Bewegungsentscheidungen simuliert und auf eine halbzylindrische Leinwand projiziert. Die Versuchspersonen lernten den Hin- und Rückweg zwischen zwei lokalen Landmarken. In der Testphase wurden einzelne Kreuzungen angefahren und die Bewegungsentscheidung der Versuchsperson aufgezeichnet. Wir führten zwei Experimente durch, die in der Testphase Landmarkenveränderungen beinhalteten. Im ersten wurde widersprüchliche lokale und globale Landmarkeninformation dargeboten; dies wurde durch Umstellen der Landmarken erreicht. Im zweiten Experiment wurde entweder die lokale oder globale Landmarkeninformation entfernt. Die Ergebnisse zeigen, daß sowohl lokale als auch globale Landmarken für Wegfindeaufgaben verwendet wurden. Jedoch verlassen sich unterschiedliche Versuchspersonen auf unterschiedliche Strategien. Im ersten Experiment (sich widersprechende lokale und globale Landmarkeninformation) verwendeten einige der Versuchspersonen nur lokale Landmarken, während andere nur globalen Landmarken vertrauten. Weitere Versuchspersonen verwendeten an einem Platz lokale und am anderen Platz globale Landmarken. Als wir im zweiten Experiment einen Landmarkentyp entfernten, konnte der andere Typ von fast allen Versuchspersonen verwendet werden. Dies zeigt, daß Information über den nicht beachteten Landmarkentyp im Gedächtnis gespeichert war, und bei Bedarf verwendet werden kann. no notspecified http://www.kyb.tuebingen.mpg.de//fileadmin/user_upload/files/publications/pdf321.pdf published -82 15017 15422 277 7 SD Geiger HA Mallot S Gillner Tübingen, Germany1998-02-00 75 1. Tübinger Wahrnehmungskonferenz (TWK 98) Spatial behavior in humans and animals includes a wide variety of behavioral competences that make use of many sensory cues, including vision. The visual input contains various cues about the observers current position (e.g., from views and local landmarks), the compass direction (e.g., provided by global landmarks), and egomotion (e.g., from optic flow). Here we investigate the role of global vs. local landmarks in a route finding task. If navigation relies more on ‘global’ landmarks for a route finding task then an allocentric description should be remembered; such as “When you reach the church square, go towards the tower on the mountain”. Alternatively, ‘local’ landmarks could guide navigation decisions by view-movement associations; e.g. “When you come to the church, turn right”. Evidence for the last strategy was presented by Gillner and Mallot (Journal of Cognitive Neuroscience, in press). We performed an experiment in a virtual environment called “Hexatown”. Hexatown consists of a regular hexagonal grid of junctions joined together by streets. At each junction there are three buildings, or other objects. Additionally, we provide global direction or compass information by placing six global landmarks distributed equally on a mountain range surrounding Hexatown. Subjects navigated in Hexatown by pressing the buttons of a computer mouse. According to their movement decisions, egomotion was simulated. Subjects had to learn the route back and forth between two specific buildings. Awareness of global landmarks was assessed by an additional pointing task. In the test-phase individual junctions were approached and the subjects’ movement decision was recorded. Two conditions were used: a ‘consistent’ condition, which was the same as in the training phase, and a ‘conflict’ condition. Conflict was produced by transposition of objects such that the global and local strategies predicted different movement decisions. In the consistent condition, i.e., with unchanged objects, 20 subjects made 85% correct decisions out of a total of 160. In the conflict condition, 77% of the decisions were in agreement with the local and 23% with the global strategy. This supports our previous finding that local views play a dominant role in making route judgements. In a control experiment we tested whether subjects could use the global landmarks at all. We reduced the local information in the maze and instructed the subjects to attend to the global landmarks. In this case, 76% of the 80 decisions were consistent with global landmark information. Since no local information was provided in this control experiment the remaining 24% of the decisions were errors. We conclude that subjects prefer local landmarks when available, but are also able to use global landmarks for route finding, when they are instructed to attend to them. no notspecified http://www.kyb.tuebingen.mpg.de/ published -75 15017 15422 282 7 HA Mallot S Gillner SD Geiger Tübingen, Germany1998-02-00 33 1. Tübinger Wahrnehmungskonferenz (TWK 98) In the development of navigation behavior, one important step is the transition from routes to maps. Route behavior is characterized by the repetition of previously learned sequences of sensory input and performed movements and can be modeled by chains of stimulus-response-stimulus (SRS) associations. The current view (“local position information”) elicits a movement decision from which in turn the next view may be expected. For each goal, the whole route has to be learned and stored, even if routes to different goals share common segments. Map behavior makes use of goal independent knowledge of the spatial layout of the environment; such knowledge is usually called a cognitive map. In a series of experiments using virtual reality technology, we investigated the navigation ability of human subjects. The maze was composed of streets forming a regular hexagonal grid and buildings placed at the junctions in the angles between the streets (“Hexatown”). Subjects performed simulated movements by hitting the buttons of a computer mouse. Movement started and ended at so-called decision points, i.e. the junctions of the streets. Pure turns could be performed in steps of 60 degrees. When looking into a street, a translation down that street could be performed that ended at the next junction. Subjects were released at some junction and had to find various buildings presented to them as a printout on a sheet of paper (see Gillner and Mallot, J. Cogn. Neurosci., in press). In the talk, we will review a number of experiments performed in the Hexatown environment. With respect to the route vs. map dichotomy, three important results have been obtained: 1. Persistence: Subjects tend to repeat movement decisions when coming back to a previously visited view. This is evidence for simple stimulus-response associations as would be expected in route memory. 2. View-based representation: After learning a given route, we replaced individual buildings along that route. Results indicate that movements are associated to views of individual buildings, not to configurations of buildings at each junction (“places”). 3. Transfer: Subjects were able to transfer knowledge from one route to another. This is an indication of goal-independent knowledge (cognitive map). In conclusion, the data show that humans simultaneously use both route and map type knowledge of the environment. A common framework for the two types of knowledge based on the view-graph (Schölkopf and Mallot, Adaptive Behavior 3:311-348, 1995) will be discussed. no notspecified http://www.kyb.tuebingen.mpg.de/ published -33 15017 15422 407 7 SD Geiger S Gillner HA Mallot Helsinki, Finland1997-08-00 56 20th European Conference on Visual Perception Motivated by the results of Gillner and Mallot (1996 Perception 25 Supplement, 93) implying that local views are basic elements for a spatial representation, we studied the role of global versus local landmarks using a route-finding task. Our hypotheses were: (i) A global navigation strategy relying on allocentric movement decisions is used, eg "go from this place towards the chapel on the hill", or (ii) a local navigation strategy based on view--movement associations is used, eg "at the red building go right". We performed an experiment in a computer graphics town based on a hexagonal grid structure. At each intersection we placed three different buildings. We also provided global direction information by placing six global landmarks distributed equally along a mountain range. Subjects had to learn the back and forth route between two buildings, not knowing that after a learning phase the location of buildings at a particular junction would be changed. These changes produced conflicting global and local information. In the test-phase, the subject approached individual junctions in both learned and novel directions and the movement decisions were recorded. In a control condition with unchanged places twenty subjects made correct decisions for 136 of 160 movements. In the experimental conflict condition 123 decisions were consistent with a local and 37 with a global strategy. This supports our previous finding that local views play a dominant role in making route judgements. Approaching a junction from a learned direction leads to more accurate movement decisions than approaching it from a novel direction, even if the global landmarks are available, which provides further support for the local-view hypothesis. no notspecified http://www.kyb.tuebingen.mpg.de/ published -56 15017 15422 406 7 SD Geiger S Gillner HA Mallot Göttingen, Germany1997-05-00 993 25th Göttingen Neurobiology Conference no notspecified http://www.kyb.tuebingen.mpg.de/ published -993 15017 15422 178 15 SD Steck 2000-00-00 no notspecified published 15017 15422