Time, distance, and feature trade-offs in visual apparent motion.

A model of visual apparent motion is derived from 4 observations on path selection in ambiguous displays in which apparent motion of illuminated dots could, in principle, be perceived along many possible paths: (a) Whereas motion over each path is clearly visible when its stimulus is presented in isolation, motion is usually seen over only 1 path when 2 or more such stimuli are combined (competition). (b) Path selection is nearly independent of viewing distance (scale invariance). (c) At transition points between paths i and j (where apparent motion is equally likely to be perceived along i and j), the time t and distance d between successive points along the paths are described by a log linear d/t relationship. (d) When successive elements along a path differ in orientation or size, the perceived motion along this path is not necessarily weaker than motion along a path composed entirely of identical elements. The model is a form of strength theory in which the path with greatest strength becomes the dominant path. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)