Abstract
Purpose: A consequence of human locomotion (walking, running) is the occurrence of related eye (EM) and head (HM) movements, which could potentially distort locomotion-produced flow field information. This information is normally used to guide many visual tasks. We were interested in comparing visual performance during locomotion and standing for various tasks. Methods: We recorded EM and HM (EyeLink II eye tracker with scene camera) when observers were standing, walking or running on a treadmill while observing flow fields or other stimuli for various visual tasks that were projected on a large screen. In one experiment, baseline data were collected for fixations and pursuit movements. In another, accuracy of target pursuit was determined. In others, velocity discrimination thresholds or visual search efficiency were measured. Results: We analyzed horizontal and vertical EM and HM and compared the results for standing to those for the locomotion conditions. In most cases, performance during walking and running was comparable, and sometimes even better, than during standing. This was true even though HM were only partially offset by stabilizing EM, leaving considerable amounts of noisy distortions of the flow fields. Conclusion: The fact that visual performance suffered little during locomotion suggests that there exist various mechanisms, in addition to extra-retinal feedback, that can compensate for the extra noise produced by locomotion.