Similarity in motion binds and bends judgments of aspect ratio

We investigated whether the visual system quickly shifts between attractive and repulsive distortions when the grouping state between a pair of shapes changes on a moment-to-moment basis. Observers viewed a pair of ellipses that differed in terms of how flat or tall they were and reported the aspect ratio of one ellipse from the pair. Each ellipse was defined by a cloud of coherently moving dots, and the dots within the two ellipses had either the same or different directions of motion, varying from trial to trial. We found that reports of the cued ellipse’s aspect ratio were repelled from the aspect ratio of the uncued ellipse when the shapes had different directions of motion compared to when they had the same direction of motion.

本研究旨在探究：当一对图形的分组状态随时间实时变化时，视觉系统是否会在吸引性畸变与排斥性畸变之间快速切换。实验中，观察者将观看一对长宽比例各异（或扁或高）的椭圆，并报告该组椭圆中指定椭圆的长宽比。每个椭圆均由一片相干运动点云（coherently moving dots）所定义，且两个椭圆内的点云运动方向可相同或相异，该变量在各试次(trial)间各不相同。研究结果表明：相较于两椭圆内点云运动方向一致的情况，当两者运动方向不同时，被试对目标椭圆长宽比的报告结果会偏离非目标椭圆的长宽比，呈现出排斥性畸变效应。