The use of landmark-based wayfinding strategies across the adult lifespan.

Abstract

Individuals can employ different landmark-based wayfinding strategies to acquire spatial knowledge and support navigation. Allocentric strategy use is associated with a cognitive representation of a learned environment that allows flexible navigation, while egocentric strategy use is associated with uni-directional knowledge that only supports accurate navigation in tasks that involve reproducing learned behaviours. While many studies have investigated strategy use during navigation, how strategy use develops during spatial learning remains under- researched. Therefore, this thesis primarily investigated the processes underlying strategy selection. Participants’ strategy preference during various navigation tasks, including a novel strategy assessment paradigm developed specifically for this research, revealed that individuals adopt the most accurate strategy available – be it allocentric or egocentric – in accordance with the demands of the concurrent navigation task. Interestingly, when allocentric knowledge was required for accurate navigation, participants initially employed a suboptimal egocentric strategy before switching to an allocentric strategy, suggesting that egocentric knowledge precedes allocentric knowledge. Finally, participants were not subject to performance-related decrements associated with the effort of switching strategies. Interestingly, during spatial learning, participants acquired spatial knowledge related to alternative strategies, and selectively encoded landmarks that were compatible with the use of multiple strategies, which may explain why switching wayfinding strategies is cognitively efficient. This thesis also investigated the effects of aging on strategy selection. Strategy preference changes across the adult lifespan, with decreasing allocentric strategy use primarily attributed to reduced hippocampal function, and impaired egocentric strategy use associated with age-related learning and memory deficits. Analysis revealed that older adults exhibited a task-independent preference for egocentric strategy use, and therefore experienced difficulty with tasks that required allocentric knowledge. However, when egocentric strategy use most efficiently supported accurate navigation, younger and older adults performed similarly, suggesting that egocentric strategy use is largely unaffected by aging. Finally, age differences in strategy preference and spatial learning were observed when the most efficient route learning strategy differed between decision points, supporting findings of increasing susceptibility to switching costs with age. In summary, young adults flexibly employ a variety of strategies to optimise navigational efficacy, while older adults' strategy choices are affected by age-related difficulties with allocentric strategy use and increased vulnerability to strategy switching costs.