Depth perception from second-order-motion stimuli yoked to head movement
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Updated: Aug 22, 2026

Using Eye-tracking to Assess the Relative Importance of Visual and Vestibular Input to Subcortical Motion Processing in the Roll Plane
Published on: August 22, 2025
Makoto Ichikawa1, Shin'ya Nishida, Hiroshi Ono
1Department of Perceptual Sciences and Design Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, 755-8611, Japan. ichikawa@yamaguchi-u.ac.jp
Abstract:
We examined whether depth perception was produced by the parallax of second-order motion (i.e., movement of non-luminance features, such as flicker, texture size modulation, or contrast modulation that moved in synchrony with lateral head movement). The results, obtained with second-order motion from a simple grating stimuli, showed that depth order was judged correctly with probabilities well above chance, but the reported depth magnitude did not co-vary with parallax magnitude. When we used a complex spatial pattern for which feature tracking was difficult, the accuracy of depth-order judgments descended to chance level. Our results suggest that the visual system (a) can detect the correct depth order by tracking a relative shift in the salient features of a stimulus pattern, but (b) cannot determine depth magnitude from a velocity field given by second-order-motion stimuli.
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