September 2019
Volume 19, Issue 10
Open Access
Vision Sciences Society Annual Meeting Abstract  |   September 2019
‘Explaining Away’ Cue Conflicts for Motion-in-Depth
Author Affiliations & Notes
  • Ross Goutcher
    Psychology, Faculty of Natural Sciences, University of Stirling
  • Lauren Murray
    Psychology, Faculty of Natural Sciences, University of Stirling
  • Brooke Benz
    Psychology, Faculty of Natural Sciences, University of Stirling
    Psychology, University of Edinburgh
Journal of Vision September 2019, Vol.19, 235d. doi:
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Ross Goutcher, Lauren Murray, Brooke Benz; ‘Explaining Away’ Cue Conflicts for Motion-in-Depth. Journal of Vision 2019;19(10):235d.

      Download citation file:

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

  • Supplements

When an object moves towards or away from an observer, the visual system is presented with multiple cues to its motion-in-depth, including changes in both retinal image size and relative disparity. When these cues are put into conflict, the resulting stimulus is consistent with an object moving in depth while changing in physical size. We examined the conditions under which observers ‘explain away’ such conflict between cues as due to a change in object size. Participants were presented with two intervals, each containing a textured, fronto-parallel surface with motion-in-depth described by a triangular waveform. One interval contained a stimulus where changing size and changing disparity cues specified the same motion-in-depth. These cues were then placed into conflict in the target interval by introducing differences in the amplitude, phase or wavelength of the motion-in-depth waveform. Participants were asked to detect the interval containing the object that changed in physical size, with 75% correct thresholds measured for each conflict type. Thresholds for conflicts in amplitude, phase and wavelength were translated into equivalent changes in physical size. Participants correctly discriminated the target interval when cue conflict was consistent with size variation of around 4–6% of the object’s simulated size. Size change thresholds were largely comparable across conflict types, although phase differences were slightly easier to detect. In subsequent experiments, we examined the effects of conflict on the perception of speed-in-depth. Results suggest a limited effect of perceived size change on speed-in-depth discrimination. To account for performance across these tasks, we generated likelihood functions describing the probability of changes in image size or disparity, given object size and speed. We show that the ‘explaining away’ of motion-in-depth cue conflicts can be described in terms of either discrepancies between cues, or through discrepancies between predicted and measured image size changes over time.


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.