Interaction between stimulus contrast and pre-saccadic crowding

Objects that are briefly flashed around the time of saccades are mislocalized. Previously, robust interactions between saccadic perceptual distortions and stimulus contrast have been reported. It is also known that crowding depends on the contrast of the target and flankers. Here, we investigated how stimulus contrast and crowding interact with pre-saccadic perception. We asked observers to report the orientation of a tilted Gabor presented in the periphery, with or without four flanking vertically oriented Gabors. Observers performed the task either following a saccade or while maintaining fixation. Contrasts of the target and flankers were independently set to either high or low, with equal probability. In both the fixation and saccade conditions, the flanked conditions resulted in worse discrimination performance—the crowding effect. In the unflanked saccade trials, performance significantly decreased with target-to-saccade onset for low-contrast targets but not for high-contrast tar...在眼跳（saccade）前后短暂闪现的物体易发生位置错位。既往已有研究证实，眼跳引发的知觉扭曲与刺激对比度之间存在稳健的交互效应。此外，视觉拥挤效应（crowding）的强弱依赖于目标与侧翼刺激的对比度。本研究旨在探究刺激对比度与视觉拥挤效应如何与眼跳前知觉发生交互作用。我们要求被试报告外周视野中呈现的倾斜加博（Gabor）刺激的朝向，实验中该刺激可伴随或不伴随四个垂直朝向的侧翼加博刺激。被试需在两种任务条件下完成任务：要么在完成眼跳后进行判断，要么保持注视状态进行判断。目标与侧翼刺激的对比度可独立设置为高或低，二者出现概率均等。在注视与眼跳两种条件下，伴随侧翼刺激的试次均表现出更差的辨别成绩——即视觉拥挤效应。在无侧翼刺激的眼跳试次中，低对比度目标的辨别成绩随目标呈现至眼跳起始的时间间隔显著下降，而高对比度目标则未出现该现象（原文内容截断）。