Abstract
Purpose: One little-studied aspect of the vision-action linkage is the role of visual information for self-motion monitoring. Non-visual path integration is sometimes enhanced when previews of non-origin destinations are provided, whereas previews of the origin are of little benefit. One idea is that in prior studies, vision of non-origin targets enhanced updating by supplying information for active control. Another possibility is that updating relative to forward destinations is privileged compared to rearward ones. Previous work addressing the second idea have used complex paths involving turns; here, we used simplified paths involving only straight segments. Method: Ten observers viewed a stimulus (0, 2.5, or 5 m away) directly in front of them in a well-lit room. They then donned a blindfold and began walking along a straight path. An experimenter specified the path length (1.5 – 6 m) and the walking speed (slow, medium, fast) after vision was obscured by walking beside the observer. After stopping, observers verbally estimated the distance to the stimulus and stated whether it lay in front or behind them. Thus, updating relative to both rearward and forward stimuli was measured. Results: Perceived Walked Distances were calculated based on the above responses and verbal estimates of egocentric distances (obtained in a pre-test under similar conditions). Walked distances were generally underestimated (by about 23%); however, errors were smaller in the context of forward reference stimuli than rearward ones (−11% vs. −35%, p < .05). Conclusions: Object locations seen during a preview affect self-motion monitoring in a subsequent nonvisual walking task. In particular, updating can be enhanced when an observer approaches a remembered location vs. walking away from it. This effect may be related to the benefit supplied by vision when it is used for active control of locomotion.