Age-related changes in gaze sampling strategies during obstacle navigation

Abstract

BackgroundAppropriate coordination of gaze behavior and body motion is essential for navigating cluttered environments. This is often complicated by having to contend with a concurrent secondary task, like engaging in a conversation or looking for relevant landmarks. However, there is little evidence of how aging and multitasking affects how gaze is deployed during obstacle navigation to guide our movements. Research questionHow do gaze patterns differ between young and older adults when navigating around a series of obstacles under dual-task conditions? Methods17 young adults and 17 older adults navigated around vertically-oriented obstacles in isolation (i.e., single-task condition) and while engaging in a concurrent backward-counting or visual search task (i.e., dual-task conditions). In the visual search condition, participants had to identify the location of an object (i.e., a black shape on a tile) along the perimeter of the pathway, simulating a landmark. We quantified the spatial-temporal pattern of gaze to obstacles relative to body position, as well as the frequency and duration of gaze fixations to obstacles, route-planning features, and landmarks. ResultsWe found that older adults transferred gaze away from obstacles earlier and contacted obstacles more frequently than young adults. However, the proportion of fixation number and duration to obstacles did not differ between groups in any condition. In addition, older adults had to allocate gaze to landmarks to a greater extent in the visual search condition—at the expense of fixating route-planning areas—to maintain similar search performance in the dual-task condition compared to the single-task condition. SignificanceOlder adults use different gaze strategies and have greater difficulty under dual-tasking conditions than young adults when navigating around a series of obstacles. We suggest that deficits in visual working memory and/or divided attention may explain these results.