Abstract

When studying visual motion from the vantage point of psychophysics, we can discern two broad sets of research questions. First and most common are questions regarding the encoding of retinal image velocities and the uses to which this image velocity information is put. This is the area where psychophysics and physiology have had the most success, and several examples are discussed. Second and relatively unexplored is the higher-order question as to what gives rise to the perception of motion. In this context we present evidence and demonstrations from which we draw the following conclusions: (1) the perception of motion is dictated by many cues other than image velocity, including occlusion and stereopsis; (2) the actual perception of motion is often an effect rather than a cause and can be understood in terms of the propagation of 3-D real-world constraints.

© 1987 Optical Society of America