Spatial localization in saccade and pursuit-eye-movement conditions: A comparison of perceptual and motor measures

Abstract

The ability to localize the spatial position of a visual target fixated by a saccade or a pursuit eye movement was examined using motor and perceptual measures. When subjects were asked to reproduce the distance of the target displacement (perceptual measure), the produced distance in the pursuit-eye-movement conditions was shorter than that in the saccade conditions. The underestimation of the target displacement in the pursuit-eye-movement conditions was also found when subjects pointed manually to the position of the just extinguished visual target (motor measure) from the original starting position of the moving target. However, when the starting position of the pointing hand was varied from trial to trial, no difference in pointing performance was found between the two eye-movement conditions. The results provide clear evidence that there is a substantial difference between motor and perceptual localization of the visual target fixated by a saccade or a pursuit eye movement. © 1985 Psychonomic Society, Inc.