THE INFLUENCE OF DEPTH-CUES ON PATHS OF APPARENT MOTION

In the present study, we examined how the disparities in length, size or luminance between stimuli would affect the choice of apparent motion path when a stationary stimulus was spatially interposed between two apparent motion stimuli. The results were as follows; (1) the perceived motion path in depth differed in quality as to whether or not there was a depth impression based on the disparity; (2) with depth cue, say, when apparent motion stimuli were larger (or smaller) in length, size or luminance than the stationary stimulus, subjects often saw a single object translating in the frontal plane, in front of (or behind the stationary stimulus; (3) on the other hand, with no depth cue, they saw indiscriminated motion in depth or curving motions, especially back-curving motion, at the stationary stimulus. It was suggested that in apparent motion the visual system avoids a collision between a moving object and interposed stimulus, by choosing a path of translating motion in depth, but it occasionally shows a tendency to choose a path of motion, curving behind the interposed stimulus.