Effect of stimulus onset delay in visual search by monkeys

Abstract

Control of visual fixations was studied as three stump-tailed macaques (Macaca arctoides) performed on a search task. The presentation of each visual stimulus was delayed for a short time (0-163 msec) after the beginning of a fixation on the location of that stimulus. The duration of visual fixations increased as a function of stimulus onset delay up to 130 msec. However, the increase in fixation duration was only half the stimulus onset delay imposed. This result suggests that oculomotor reactions are facilitated by longer foreperiods in a manner similar to other disjunctive reactions. © 1976, The Psychonomic Society, Inc. All rights reserved.