Is Optic Flow Used to Guide Walking While Wearing a Displacing Prism?
- 1 July 2001
- journal article
- research article
- Published by SAGE Publications in Perception
- Vol. 30 (7), 811-818
- https://doi.org/10.1068/p3160
Abstract
Rushton et al (1998 Current Biology8 1191–1194) recently showed that walkers wearing displacing prisms follow curved trajectories determined by the perceived direction of their target. This suggests that optic flow is not important in guidance, since flow cues are unaffected by the prism and should allow a straight, direct trajectory. We replicated Rushton et al's result but also tried to rule out an important artifact associated with the prism. Prisms restrict the field of view and, particularly, access to the foreground optic flow that is likely to be important in providing guidance cues. We found that performance did not improve when walkers directed their gaze to include the foreground flow, suggesting that Rushton et al's results were not due to this artifact. On the other hand, performance did reliably improve when subjects reduced their viewing height by crawling towards the target. This improvement may be due to coarsening of the visual texture or to increased salience of alignment and motion-parallax cues. Whatever its cause, the improvement demonstrates that guidance is not determined only by perceived target direction and that, under some conditions, flow may be important.Keywords
This publication has 10 references indexed in Scilit:
- Optic flow is used to control human walkingNature Neuroscience, 2001
- Reply to Harris and RogersTrends in Cognitive Sciences, 1999
- Going against the flowTrends in Cognitive Sciences, 1999
- Perception of self-motion from visual flowTrends in Cognitive Sciences, 1999
- Human heading judgments and object-based motion informationVision Research, 1999
- Guidance of locomotion on foot uses perceived target location rather than optic flowCurrent Biology, 1998
- Estimating heading during eye movementsVision Research, 1994
- Eye movements and optical flowJournal of the Optical Society of America A, 1990
- Direction of self-motion is perceived from optical flowNature, 1988
- Perception of translational heading from optical flow.Journal of Experimental Psychology: Human Perception and Performance, 1988