Practice reduces suppression in metacontrast and in apparent motion

Abstract

A target display consisting of eight dots drawn randomly from a nine-dot square matrix was displayed for 10 msec and was followed, after intervals ranging from 0 to 160 msec, by either two flanking matrices (metacontrast condition) or one flanking matrix (apparent-motion condition). Observers were required to name the location of the missing dot within the target matrix. Identical U-shaped functions of perceptual suppression of the target matrix were obtained in both paradigms. In both cases, level of suppression decreased rapidly with practice so that performance became virtually unimpaired after five testing sessions. The basis of the practice effects was examined in Experiment 2 and was shown to reflect changes in criterion content. © 1984 Psychonomic Society, Inc.