911³Ô¹Ï

How cognitive and biomechanical factors influence gaze and path choice while walking

When making path decisions, individuals use gaze shifts to gather relevant information about the terrain ahead. In these situations, the brain must prioritize between multiple competing information sources. Which factors the brain uses to bias gaze toward certain sources over others is unclear. The goal of this thesis was to explore how one’s confidence in their ability to walk across terrain (i.e., self-efficacy beliefs) and motor cost influence gaze behaviour and path choice. In experiment 1, we determined how self-efficacy affects gaze behaviour and path choice. We used a forced-choice walking paradigm, where participants chose between two paths composed of realistic terrain images. Greater self-efficacy in walking across a path led to increased gaze directed at that path, which increased the likelihood of choosing it. In experiment two, we determined how self-efficacy affects gaze and path choice when choosing between paths with different predicted costs and/or terrains. Participants chose between two paths that varied in simulated terrain (affecting self-efficacy), length (affecting motor cost), or both. When manipulated separately, participants were more likely to look at paths where they had higher self-efficacy or that were shorter, and their walking decisions mirrored these gaze patterns. However, when both factors were manipulated simultaneously, participants looked increasingly at the longer path when their self-efficacy regarding the shorter path decreased. Participants frequently chose the path rated higher in terms of self-efficacy, regardless of the terrain’s predicated cost. In experiment three, we determined how gaze behaviour and path choice change as people learn to walk with new cost consequences. Participants chose between three paths while wearing leg exoskeletons, which altered the cost consequences of walking depending on the path. Participants used different strategies to learn the optimal path, and these strategies influenced their learning rates and ability to transfer knowledge to an environment with different paths. As participants learned the cost consequences, their gaze behaviour increasingly reflected and predicted their walking decisions towards the most optimal path. Overall, this thesis provides insight into how different cognitive and biomechanical factors shape gaze behaviour and walking decisions, which may help to refine computational decision-making models.