Depth perception from second-order-motion stimuli yoked to head movement.
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.
Ichikawa
Makoto
M
Department of Perceptual Sciences and Design Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube, 755-8611, Japan. ichikawa@yamaguchi-u.ac.jp
Nishida
Shin'ya
S
Ono
Hiroshi
H
D003463:Cues; D003867:Depth Perception / Q000502:physiology*; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods