The two-process distinction in apparent motion.

Traces the historical development of the notion that two processes mediate apparent motion percepts, examines evidence regarding their existence, and summarizes associated characteristics. The short-range process is assumed to reflect the activity of low-level directionally selective motion detectors, have a relatively small spatial integration range, and be favored by short stimulus durations and interstimulus intervals. The long-range process is thought to reflect higher order perceptual activity, match stimulus elements over relatively large retinal distances, and be favored by longer stimulus durations and interstimulus intervals. Criteria for associating different percepts with functionally different processes are advanced and applied. The theoretical status of the two-process distinction is examined, and a heuristic model of motion perception is presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)