T Meilinger

The Network of Reference Frames Theory: A Synthesis of Graphs and Cognitive Maps

The network of reference frames theory explains the orientation behavior of human and non-human animals in directly experienced environmental spaces, such as buildings or towns. This includes self-localization, route and survey navigation. It is a synthesis of graph representations and cognitive maps, and solves the problems associated with explaining orientation behavior based either on graphs, maps or both of them in parallel. Additionally, the theory points out the unique role of vista spaces and asymmetries in spatial memory. New predictions are derived from the theory, one of which has been tested recently.

Is the Map in Our Head Oriented North

We examined how a highly familiar environmental space—one’s city of residence—is represented in memory. Twenty-six participants faced a photo-realistic virtual model of their hometown and completed a task in which they pointed to familiar target locations from various orientations. Each participant’s performance was most accurate when he or she was facing north, and errors increased as participants’ deviation from a north-facing orientation increased. Pointing errors and latencies were not related to the distance between participants’ initial locations and the target locations. Our results are inconsistent with accounts of orientation-free memory and with theories assuming that the storage of spatial knowledge depends on local reference frames. Although participants recognized familiar local views in their initial locations, their strategy for pointing relied on a single, north-oriented reference frame that was likely acquired from maps rather than experience from daily exploration. Even though participants had spent significantly more time navigating the city than looking at maps, their pointing behavior seemed to rely on a north-oriented mental map.

Local and global reference frames for environmental spaces

Two experiments examined how locations in environmental spaces, which cannot be overseen from one location, are represented in memory: by global reference frames, multiple local reference frames, or orientation-free representations. After learning an immersive virtual environment by repeatedly walking a closed multisegment route, participants pointed to seven previously learned targets from different locations. Contrary to many conceptions of survey knowledge, local reference frames played an important role: Participants performed better when their body or pointing targets were aligned with the local reference frame (corridor). Moreover, most participants turned their head to align it with local reference frames. However, indications for global reference frames were also found: Participants performed better when their body or current corridor was parallel/orthogonal to a global reference frame instead of oblique. Participants showing this pattern performed comparatively better. We conclude that survey tasks can be solved based on interconnected local reference frames. Participants who pointed more accurately or quickly additionally used global reference frames.

From isovists via mental representations to behaviour: first steps toward closing the causal chain

This paper addresses the interactions between human wayfinding performance, the mental representation of routes, and the geometrical layout of path intersections. The conclusions of this paper are based on the results of a virtual reality empirical experiment. The study consisted of a route-learning and reproduction task and two choice reaction tasks measuring the acquired knowledge of route decision points. In order to relate the recorded behaviour to the geometry of the environment, a specific adaptation of an isovist-based spatial analysis that accounts for directional bias in human spatial perception and representation was developed. The analyses applied provided conclusive evidence of correspondences between the geometrical properties of environments as captured by isovists and their mental representations.

Finding the way inside: linking architectural design analysis and cognitive processes

The paper is concerned with human wayfinding in public buildings. Two main aspects of wayfinding difficulties are considered: architectural features of the building and cognitive processes of the agent. We conducted an empirical study in a complex multi-level building, comparing performance measures of experienced and inexperienced participants in different wayfinding tasks. Thinking aloud protocols provide insights into navigation strategies, planning phases, use of landmarks and signage, and measures of survey knowledge. Specific strategies for navigation in multi-level buildings, like the floor strategy, are identified and evaluated. An architectural analysis of the building is provided and possible causes for navigation problems are discussed. Different architectural features of the building are investigated with respect to human spatial cognition and usability issues. Finally we address potential benefits for the architectural design process and discuss options for further research.

Spatial and temporal aspects of navigation in two neurological patients

We present two cases (A.C. and W.J.) with navigation problems resulting from parieto-occipital right hemisphere damage. For both the cases, performance on the neuropsychological tests did not indicate specific impairments in spatial processing, despite severe subjective complaints of spatial disorientation. Various aspects of navigation were tested in a new virtual reality task, the Virtual Tübingen task. A double dissociation between spatial and temporal deficits was found; A.C. was impaired in route ordering, a temporal test, whereas W.J. was impaired in scene recognition and route continuation, which are spatial in nature. These findings offer important insights in the functional and neural architecture of navigation.

MPI CyberMotion Simulator: implementation of a novel motion simulator to investigate multisensory path integration in three dimensions.

Path integration is a process in which self-motion is integrated over time to obtain an estimate of ones current position relative to a starting point 1. Humans can do path integration based exclusively on visual 2-3, auditory 4, or inertial cues 5. However, with multiple cues present, inertial cues - particularly kinaesthetic - seem to dominate 6-7. In the absence of vision, humans tend to overestimate short distances (<5 m) and turning angles (<30°), but underestimate longer ones 5. Movement through physical space therefore does not seem to be accurately represented by the brain. Extensive work has been done on evaluating path integration in the horizontal plane, but little is known about vertical movement (see 3 for virtual movement from vision alone). One reason for this is that traditional motion simulators have a small range of motion restricted mainly to the horizontal plane. Here we take advantage of a motion simulator 8-9 with a large range of motion to assess whether path integration is similar between horizontal and vertical planes. The relative contributions of inertial and visual cues for path navigation were also assessed. 16 observers sat upright in a seat mounted to the flange of a modified KUKA anthropomorphic robot arm. Sensory information was manipulated by providing visual (optic flow, limited lifetime star field), vestibular-kinaesthetic (passive self motion with eyes closed), or visual and vestibular-kinaesthetic motion cues. Movement trajectories in the horizontal, sagittal and frontal planes consisted of two segment lengths (1st: 0.4 m, 2nd: 1 m; ±0.24 m/s2 peak acceleration). The angle of the two segments was either 45° or 90°. Observers pointed back to their origin by moving an arrow that was superimposed on an avatar presented on the screen. Observers were more likely to underestimate angle size for movement in the horizontal plane compared to the vertical planes. In the frontal plane observers were more likely to overestimate angle size while there was no such bias in the sagittal plane. Finally, observers responded slower when answering based on vestibular-kinaesthetic information alone. Human path integration based on vestibular-kinaesthetic information alone thus takes longer than when visual information is present. That pointing is consistent with underestimating and overestimating the angle one has moved through in the horizontal and vertical planes respectively, suggests that the neural representation of self-motion through space is non-symmetrical which may relate to the fact that humans experience movement mostly within the horizontal plane.

Ask for Directions or Use a Map: A Field Experiment on Spatial Orientation and Wayfinding in an Urban Environment

When planning a route we usually study a map, ask other people for verbal directions, or use a route planner. Which source of information is most helpful? This experiment investigated human wayfinding and knowledge acquisition in urban environments. Participants were required to retrace two different routes learned either from route maps, or from verbal directions. This research shows that both maps and verbal directions are equally useful tools for conveying wayfinding knowledge. Even the survey knowledge of map‐learners was not better. The authors argue that both verbal directions and maps are memorized in a language‐based format, which is mainly used for wayfinding.

Learning New Sensorimotor Contingencies: Effects of Long-Term Use of Sensory Augmentation on the Brain and Conscious Perception

Theories of embodied cognition propose that perception is shaped by sensory stimuli and by the actions of the organism. Following sensorimotor contingency theory, the mastery of lawful relations between own behavior and resulting changes in sensory signals, called sensorimotor contingencies, is constitutive of conscious perception. Sensorimotor contingency theory predicts that, after training, knowledge relating to new sensorimotor contingencies develops, leading to changes in the activation of sensorimotor systems, and concomitant changes in perception. In the present study, we spell out this hypothesis in detail and investigate whether it is possible to learn new sensorimotor contingencies by sensory augmentation. Specifically, we designed an fMRI compatible sensory augmentation device, the feelSpace belt, which gives orientation information about the direction of magnetic north via vibrotactile stimulation on the waist of participants. In a longitudinal study, participants trained with this belt for seven weeks in natural environment. Our EEG results indicate that training with the belt leads to changes in sleep architecture early in the training phase, compatible with the consolidation of procedural learning as well as increased sensorimotor processing and motor programming. The fMRI results suggest that training entails activity in sensory as well as higher motor centers and brain areas known to be involved in navigation. These neural changes are accompanied with changes in how space and the belt signal are perceived, as well as with increased trust in navigational ability. Thus, our data on physiological processes and subjective experiences are compatible with the hypothesis that new sensorimotor contingencies can be acquired using sensory augmentation.

The integration of spatial information across different viewpoints

The integration of spatial information perceived from different viewpoints is a frequent, yet largely unexplored, cognitive ability. In two experiments, participants saw two presentations, each consisting of three targets—that is, illuminated tiles on the floor—before walking the shortest possible path across all targets. In Experiment 1, participants viewed the targets either from the same viewpoint or from different viewpoints. Errors in recalling targets increased if participants changed their viewpoints between presentations, suggesting that memory acquired from different viewpoints had to be aligned for integration. Furthermore, the error pattern indicates that memory for the first presentation was transformed into the reference frame of the second presentation. In Experiment 2, we examined whether this transformation occurred because new information was integrated already during encoding or because memorized information was integrated when required. Results suggest that the latter is the case. This might serve as a strategy for avoiding additional alignments.