ABSTRACT

Everyday perception occurs in a context of nested motions. Eyes move within heads, heads move on bodies, and bodies move in surroundings that are filled with objects, many of which can themselves move (Gibson, 1966). Motion is omnipresent in perception. Stabilize an image on the retina and it rapidly becomes imperceptible (Pritchard, 1961). Not only is motion a necessary condition for perception, but it is also a sufficient condition for the perception of a variety of environmental properties.