November 2002
Volume 2, Issue 7
Free
Vision Sciences Society Annual Meeting Abstract  |   November 2002
Reduction of perceived visual speed during walking: Effect dependent upon stimulus similarity to the visual consequences of locomotion
Author Affiliations
  • Adrian E.I. Thurrell
    Institute of Neurology, UCL, UK
Journal of Vision November 2002, Vol.2, 628. doi:10.1167/2.7.628
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Adrian E.I. Thurrell, Adar Pelah; Reduction of perceived visual speed during walking: Effect dependent upon stimulus similarity to the visual consequences of locomotion. Journal of Vision 2002;2(7):628. doi: 10.1167/2.7.628.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

PURPOSE We reported previously that perceived optic flow speed is reduced linearly with walking speed (Thurrell et al. 1998 Perception 27 pp 147–148), a mechanism we postulate would preserve world constancy during normal self-motion. We consider here whether the reduction also occurs with visual scenes that are progressively less characteristic of upright locomotion.

METHODS Subjects viewed an optic flow reference stimulus comprising either an expanding tunnel of concentric rectangles, horizontally or vertically translating gratings, a rotating spoked wheel or, as a control condition, flashing stationary rectangles, for 15 s while walking at an instructed rate (i.e. very slow, slow… very fast). Subjects then ceased walking and attempted to match the reference optical velocity (or frequency for flashing stimulus) by adjusting a similar visual scene with a hand-held knob. Notionally, human walking corresponds principally to expanding flow, with the translating grating providing a lesser degree of correspondence and the rotating wheel still less.

RESULTS Confirming previous findings, subjects made speed settings that indicated a perceived underestimation of optic flow during walking. A weaker reduction also occurred for the gratings and one weaker still, but not significant, occurred for the rotating wheel. There was no effect of walking velocity on the perceived flashing frequency of the stationary tunnel.

CONCLUSIONS The presence of a weaker effect for the translating grating than for the expanding tunnel (and the absence of one for the rotating wheel) suggests that the influence of walking on the perception of optic flow may depend on the degree of similarity of the visual scene to that experienced during everyday, upright locomotion. The lack of an effect for the flashing tunnel suggests the mechanism acts on velocity perception per se rather than being a time-distance construct.

Thurrell, A. E. I., Pelah, A.(2002). Reduction of perceived visual speed during walking: Effect dependent upon stimulus similarity to the visual consequences of locomotion [Abstract]. Journal of Vision, 2( 7): 628, 628a, http://journalofvision.org/2/7/628/, doi:10.1167/2.7.628. [CrossRef]
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×