Related Experiment Video
Updated: Oct 5, 2026

Motion-Acuity Test for Visual Field Acuity Measurement with Motion-Defined Shapes
Published on: February 23, 2024
Stereomotion speed perception is contrast dependent
1Department of Experimental Psychology, University of Sussex, Brighton BN1 9QG, UK. kbrooks@mail.arc.nasa.gov
Abstract:
The effect of contrast on the perception of stimulus speed for stereomotion and monocular lateral motion was investigated for successive matches in random-dot stimuli. The familiar 'Thompson effect'--that a reduction in contrast leads to a reduction in perceived speed--was found in similar proportions for both binocular images moving in depth, and for monocular images translating laterally. This result is consistent with the idea that the monocular motion system has a significant input to the stereomotion system, and dominates the speed percept for approaching motion.
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