Age differences in spatial navigation: allocentric versus egocentric strategies

Spatial navigation is a complex cognitive ability, which can generally be divided into two components. One of them uses an ego perspective and includes the use of directional codes and landmarks along the way (e.g., "when I reach the pharmacy, I turn right"). It is referred to as “egocentric”. The other component is independent of one's own body position and involves the use of a mental bird’s eye view of the environment, called 'cognitive map'. This “allocentric” strategy is indispensable for finding shortcuts or ways around a roadblock. Previous research showed that spatial navigation abilities decline with advancing age, prompting older adults to limit their physical and social activities and thus to reduce independence and quality of life. It has been argued that age-related decline affects mainly allocentric rather than egocentric navigation, but direct experimental evidence for this view is still missing. The present study was designed to provide such evidence. Participants were 61 healthy volunteers (32 young, 18 - 35 years, 17 male; 29 older, 63 - 81 years, 16 male). They were tested in two game-like computer environments developed with Unreal Engine (Epic Games®). Both tests were presented in a virtual reality setting on a standard computer monitor. Participants had to find a goal by pursuing a route with 5 decision points, each with 4 branches. Test Ego provided only local landmarks (characteristic buildings in front of a featureless horizon), and test Allo only global landmarks (mountains and castles in the
distance, with all decision points looking alike). Participants performed each test eight times, with test order balanced between individuals. Performance was quantified as time to completion, distance covered and number of wrong turns. Analyses of variance yielded significant interactions of the between-factor Age Group and the within-factor Test: older adults performed similarly to young ones on the egocentric test, but performed less well than young ones on the allocentric test. We thus now have direct experimental evidence that allocentric but not egocentric navigation declines in older age.