Locomotion through surprising environments: Age effects on gaze guidance and object memory

Gaze behaviour during locomotion must balance sampling relevant information and the need for a safe and stable gait. Aging might affect this balance due to an increased risk of falling as well as decreased information seeking. Here we investigated how violations of expectations affect gaze behaviour and information uptake across age groups. We studied well-characterized samples of younger (20-40 years, N=16) and older adults (60-80 years, N=12) using a virtual reality (VR) paradigm. Participants moved through a reconstruction of a real-world university hallway wearing a VR headset. Locomotion was performed without an additional task. We placed semantically congruent (e.g., chairs) and incongruent target objects (e.g., a tuba) in the hallway to investigate how gaze behaviour during locomotion is affected by violated expectations. After the locomotion task, the participants were asked to freely recall any objects from the virtual hallway. We analyzed dwell times on objects indicating gaze behavior and object memory performance indicating information uptake. Results showed a robust attraction of gaze by incongruent objects. Dwell times on incongruent objects were increased in both age groups, however, to a larger extent in older adults. While older adults showed lower dwell times on congruent objects in comparison to younger adults, dwell times on incongruent objects were similar across age groups. Consistently, memory performance was boosted for incongruent objects and this benefit was more pronounced in older adults. Our findings indicate that surprising information attracts attention during locomotion - particularly in older adults. This attentional priorization goes along with enhanced encoding of information which could be considered a particular advantage in old age when memory resources are challenged. However, during actual locomotion in the real world such a benefit in information processing might come at the cost of reduced gait safety if processing ressources are shifted away from maintaining a stable gait.