Serial memory for landmarks encountered during route navigation

Interplay of wayfinding strategies in route repetition and route retracing

This study explores the interplay of navigation strategies in route repetition (repeating a recently travelled route) and route retracing (returning to the start location of a recently travelled route). Specifically, we investigated how sequence knowledge contributes to route repetition and retracing. In the learning phase, participants passively transported along a route. In the test phase, they were then asked to repeat or retrace the route. Decision points were either presented in an order coherent with the learning phase (from start to destination in route repetition, or from destination to start in route retracing), or in a randomised order. As expected, participants performed better in route repetition than in route retracing. Performance declined when intersections were presented in a randomised order indicating that sequence knowledge contributed to route repetition and route retracing. Presenting intersections in an order coherent with learning boosted performance specifically on the first part of the route during route repetition. This effect was not observed during route retracing. These results show that sequence knowledge is utilised differently during route repetition and retracing. We argue that participants use a "sequence of turns" strategy alongside associating landmarks with direction changes during route repetition, and that it is unlikely that route retracing relies on the same type of sequence knowledge. Instead, we believe route retracing utilises knowledge about the sequence in which decision points are encountered. Overall, the findings highlight a complex interplay of different strategies in route repetition and retracing, shedding light on how navigators utilise sequence knowledge for effective navigation.

Route sequence knowledge supports the formation of cognitive maps

In this study, we examined the extent to which knowledge about the sequence of places encountered during route learning supports the formation of a metric cognitive map. In a between subjects design, participants learned a route until they could navigate it independently without error whilst also learning information about either the identity of places along the route (Recognition Learning condition) or the sequence of places along the route (Sequence Learning condition). In a follow-up Reconstruction of Order Task, we confirmed that participants in the Sequence Learning condition had more accurate route sequence knowledge than those in the Recognition Learning condition, despite requiring the same overall number of trials to learn the route. Participants then completed a Pointing Task to assess the quality of their cognitive map of the environment. Both groups performed above chance level, showing incidental encoding of metric information, but the Sequence Learning group produced significantly lower pointing errors than the Recognition Learning group. Further, we found that route distance between pairs of places was a strong predictor of pointing error in both groups, whilst Euclidean distance between places was a significant, but weak, predictor only for the Sequence Learning condition. The results of this study demonstrate that discrete route sequence knowledge directly supports the formation of metric cognitive maps. We consider how the results are best explained by interactions between striatal route representations and hippocampal metric representations, centered around the sequence of places acting as a scaffold for the encoding of metric information.

Using a picture (or a thousand words) for supporting spatial knowledge of a complex virtual environment

External representations powerfully support and augment complex human behavior. When navigating, people often consult external representations to help them find the way to go, but do maps or verbal instructions improve spatial knowledge or support effective wayfinding? Here, we examine spatial knowledge with and without external representations in two studies where participants learn a complex virtual environment. In the first study, we asked participants to generate their own maps or verbal instructions, partway through learning. We found no evidence of improved spatial knowledge in a pointing task requiring participants to infer the direction between two targets, either on the same route or on different routes, and no differences between groups in accurately recreating a map of the target landmarks. However, as a methodological note, pointing was correlated with the accuracy of the maps that participants drew. In the second study, participants had access to an accurate map or set of verbal instructions that they could study while learning the layout of target landmarks. Again, we found no evidence of differentially improved spatial knowledge in the pointing task, although we did find that the map group could recreate a map of the target landmarks more accurately. However, overall improvement was high. There was evidence that the nature of improvement across all conditions was specific to initial navigation ability levels. Our findings add to a mixed literature on the role of external representations for navigation and suggest that more substantial intervention-more scaffolding, explicit training, enhanced visualization, perhaps with personalized sequencing-may be necessary to improve navigation ability.

Spatial Navigation and Visuospatial Strategies in Typical and Atypical Aging

Age-related spatial navigation decline is more pronounced in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) dementia. We used a realistic-looking virtual navigation test suite to analyze different aspects of visuospatial processing in typical and atypical aging. A total of 219 older adults were recruited from the Czech Brain Aging Study cohort. Cognitively normal older adults (CN; n = 78), patients with amnestic MCI (n = 75), and those with mild AD dementia (n = 66) underwent three navigational tasks, cognitive assessment, and brain MRI. Route learning and wayfinding/perspective-taking tasks distinguished the groups as performance and learning declined and specific visuospatial strategies were less utilized with increasing cognitive impairment. Increased perspective shift and utilization of non-specific strategies were associated with worse task performance across the groups. Primacy and recency effects were observed across the groups in the route learning and the wayfinding/perspective-taking task, respectively. In addition, a primacy effect was present in the wayfinding/perspective-taking task in the CN older adults. More effective spatial navigation was associated with better memory and executive functions. The results demonstrate that a realistic and ecologically valid spatial navigation test suite can reveal different aspects of visuospatial processing in typical and atypical aging.