Maladaptive bias for extrahippocampal navigation strategies in aging humans.

Efficient spatial navigation requires not only accurate spatial knowledge but also the selection of appropriate strategies. Using a novel paradigm that allowed us to distinguish between beacon, associative cue, and place strategies, we investigated the effects of cognitive aging on the selection and adoption of navigation strategies in humans. Participants were required to rejoin a previously learned route encountered from an unfamiliar direction. Successful performance required the use of an allocentric place strategy, which was increasingly observed in young participants over six experimental sessions. In contrast, older participants, who were able to recall the route when approaching intersections from the same direction as during encoding, failed to use the correct place strategy when approaching intersections from novel directions. Instead, they continuously used a beacon strategy and showed no evidence of changing their behavior across the six sessions. Given that this bias was already apparent in the first experimental session, the inability to adopt the correct place strategy is not related to an inability to switch from a firmly established response strategy to an allocentric place strategy. Rather, and in line with previous research, age-related deficits in allocentric processing result in shifts in preferred navigation strategies and an overall bias for response strategies. The specific preference for a beacon strategy is discussed in the context of a possible dissociation between beacon-based and associative-cue-based response learning in the striatum, with the latter being more sensitive to age-related changes

A vision driven wayfinding simulation system based on the architectural features perceived in the office environment

Human wayfinding in the built environment is extensively investigated in the last 50 years. One major aspect of the outcome is the decision made on the egresses based on the information perceived during the wayfinding. Information acquired of the environment could be categorized into several types, namely the verbal (information obtained from the reception, staff members, etc.), the graphic (map of the environment, signage showing the location or pointing to certain location, etc.), the architectural (entrances, stairs, corridors, etc.), and the spatial (spatial relationship of objects in the environment). Early analyses of indoor wayfinding suggested that signage and colour codes could provide landmarks, but the addition of these cues after construction can be futile. This suggests that, architectural information has a significant influence on individual’ s decision making. However, inmost researches, the function of the architectural information was underestimated -- it was often treated as the constraint of the architectural spaces. The presented research aims at developing of an agent-based system that can find certain destination in a virtual office building environment using artificial vision and cognition based on the architectural features in this built environment. During the wayfinding, this agent’ s egress choices follows an estimated model that based on experimental data with real human. Before running the experiments with real humans, pre-experiments were conducted to investigate the conditions for vision research using standard LCD monitors. The thresholds obtained in the pre-experiments for lighting in the virtual environment and for the testing environment served as input to the development of the following experiments. In the first experiment subjects were asked to make choices between two egresses in a sequence of isolated convex rooms. The architectural features of these rooms and of the egresses were varied systematically. The room features included: size and colour; while the egress features were: colour, distance, angle and width. From the collected data a preference function was estimated on egress choice given the architectural features. In the second experiment the assignment was to find the destination and then return to the start in a virtual building. Subjects executed three different assignments given different locations for the destination and the start, and every assignment was repeated two to three times subsequently. Each subject’ s routes in the experiments were recorded. From these routes search strategies used for wayfinding were determined, namely: Orientation Based, Architectural Features Based, Boundary Based, Random Choice, Minimum rooms and Shortest Distance. A preference function was estimated for the next room choice, based upon the architectural features of the current room, and the given familiarity of the environment. The implemented agent uses a simplified version of the virtual building model. This simplified version only includes those architectural elements and features that are relevant for vision driven navigation, i.e. the type of egress, egress colour, egress width, room colour and room size. Room colour is converted into three levels of grey. The agent’ s wayfinding behaviour is validated with the hit ratio, the average visit frequency of each room, and the average total number of rooms visited, respectively. The agent-based simulation system developed in not only an interpretation of the empirical findings obtained from the research, but it is also applicable for testing and evaluation purposes in architectural design problems. After certain transformations, a CAD model of an office environment can be presented to the simulation system as input. By setting the wayfinding task, the designed agent can be employed to predict how individuals may behave in this office environment in reality. This helps the architects, with regard to wayfinding efficiency and space utility, to improve their design

The Role of Slope in Human Reorientation

Studies of spatial representation generally focus on flat environments and visual stimuli. However, the world is not flat, and slopes are part of many natural environments. In a series of four experiments, we examined whether humans can use a slope as a source of allocentric, directional information for reorientation. A target was hidden in a corner of a square, featureless enclosure tilted at a 5° angle. Finding it required using the vestibular, kinesthetic and vis-ual cues associated with the slope gradient. Participants succeeded in the task; however, a large sex difference emerged. Men showed a greater ability in using slope and a greater preference for relying on slope as a searching strategy. The female disadvantage was not due to wearing heeled shoes, but was probably re-lated to a greater difficulty in extracting the vertical axis of the slope

No gender differences in egocentric and allocentric environmental transformation after compensating for male advantage by manipulating familiarity

The present study has two-fold aims: to investigate whether gender differences persist even when more time is given to acquire spatial information; to assess the gender effect when the retrieval phase requires recalling the pathway from the same or a different reference perspective (egocentric or allocentric). Specifically, we analyse the performance of men and women while learning a path from a map or by observing an experimenter in a real environment. We then asked them to reproduce the learned path using the same reference system (map learning vs. map retrieval or real environment learning vs. real environment retrieval) or using a different reference system (map learning vs. real environment retrieval or vice versa). The results showed that gender differences were not present in the retrieval phase when women have the necessary time to acquire spatial information. Moreover, using the egocentric coordinates (both in the learning and retrieval phase) proved easier than the other conditions, whereas learning through allocentric coordinates and then retrieving the environmental information using egocentric coordinates proved to be the most difficult. Results showed that by manipulating familiarity, gender differences disappear, or are attenuated in all conditions

An Initial Exploration of a Multi-Sensory Design Space: Tactile Support for Walking in Immersive Virtual Environments

Multi-sensory feedback can potentially improve user experience and performance in virtual environments. As it is complicated to study the effect of multi-sensory feedback as a single factor, we created a design space with these diverse cues, categorizing them into an appropriate granularity based on their origin and use cases. To examine the effects of tactile cues during non-fatiguing walking in immersive virtual environments, we selected certain tactile cues from the design space, movement wind, directional wind and footstep vibration, and another cue, footstep sounds, and investigated their influence and interaction with each other in more detail. We developed a virtual reality system with non-fatiguing walking interaction and low-latency, multi-sensory feedback, and then used it to conduct two successive experiments measuring user experience and performance through a triangle-completion task. We noticed some effects due to the addition of footstep vibration on task performance, and saw significant improvement due to the added tactile cues in reported user experience

The world is not flat: Can people reorient using slope?

Studies of spatial representation generally focus on flat environments and visual input. However, the world is not flat, and slopes are part of most natural environments. In a series of 4 experiments, we examined whether humans can use a slope as a source of allocentric, directional information for reorientation. A target was hidden in a corner of a square, featureless enclosure tilted at a 5° angle. Finding it required using the vestibular, kinesthetic, and visual cues associated with the slope gradient. In Experiment 1, the overall sample performed above chance, showing that slope is sufficient for reorientation in a real environment. However, a sex difference emerged; men outperformed women by 1.4 SDs because they were more likely to use a slope-based strategy. In Experiment 2, attention was drawn to the slope, and participants were prompted to rely on it to solve the task; however, men still outperformed women, indicating a greater ability to use slope. In Experiment 3, we excluded the possibility that women\u27s disadvantage was due to wearing heeled footwear. In Experiment 4, women required more time than men to identify the uphill direction of the slope gradient; this suggests that, in a bottom-up fashion, a perceptual or attentional difficulty underlies women\u27s disadvantage in the ability to use slope and their decreased reliance on this cue. Overall, a bi-coordinate representation was used to find the goal: The target was encoded primarily with respect to the vertical axis and secondarily with respect to the orthogonal axis of the slope

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Differential prioritization of intramaze cue and boundary information during spatial navigation across the human lifespan

Spatial learning can be based on intramaze cues and environmental boundaries. These processes are predominantly subserved by striatal- and hippocampal-dependent circuitries, respectively. Maturation and aging processes in these brain regions may affect lifespan differences in their contributions to spatial learning. We independently manipulated an intramaze cue or the environment’s boundary in a navigation task in 27 younger children (6–8 years), 30 older children (10–13 years), 29 adolescents (15–17 years), 29 younger adults (20–35 years) and 26 older adults (65–80 years) to investigate lifespan age differences in the relative prioritization of either information. Whereas learning based on an intramaze cue showed earlier maturation during the progression from younger to later childhood and remained relatively stable across adulthood, maturation of boundary-based learning was more protracted towards peri-adolescence and showed strong aging-related decline. Furthermore, individual differences in prioritizing intramaze cue- over computationally more demanding boundary-based learning was positively associated with cognitive processing fluctuations and this association was partially mediated by spatial working memory capacity during adult, but not during child development. This evidence reveals different age gradients of two modes of spatial learning across the lifespan, which seem further influenced by individual differences in cognitive processing fluctuations and working memory, particularly during aging