Depth perception from second-order-motion stimuli yoked to head movement

• Published in: Vision research (Oxford) Vol. 44; no. 25; pp. 2945 - 2954
• Main Authors: Ichikawa, Makoto, Nishida, Shin’ya, Ono, Hiroshi
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.11.2004; Elsevier Science
• Subjects: Biological and medical sciences; Cues; Depth magnitude; Depth order; Depth Perception - physiology; Feature tracking; Fundamental and applied biological sciences. Psychology; Head Movements - physiology; Humans; Motion parallax; Motion Perception - physiology; Pattern Recognition, Visual - physiology; Perception; Photic Stimulation - methods; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Second-order motion; Vision; Depth magnitude; Feature tracking; Motion parallax; Second-order motion; Depth order; Human; Motion; Head; Stimulus movement; Experimental study; Depth; Visual stimulus; Vision; Perception; Parallax
• ISSN: 0042-6989; 1878-5646
• DOI: 10.1016/j.visres.2004.07.003

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.