Ouhnana Marouane, Kingdom Frederick A A
Department of Ophthalmology, McGill Vision Research, Montreal, QC, Canada.
Iperception. 2016 Nov 22;7(6):2041669516677843. doi: 10.1177/2041669516677843. eCollection 2016 Nov-Dec.
The motion trajectory of an object's cast shadow has been shown to alter the perceived trajectory of a casting object, an effect that holds even if the cast shadow appears unrealistic. This raises the question of whether a cast shadow per se is necessary for this influence, a question that has been studied only with stationary targets. We examined the relative influence of a shadow and a spherical object on the perceived motion trajectory of an identical spherical object, using a paradigm similar to Kersten, Mamassian, and Knill's ball-in-box animation. We recorded both depth and height estimates of the perceived end-point of the target trajectory as a function of various target and context trajectories. Both shadows and objects significantly influenced the perceived trajectory of the target, though the influence of the shadow was overall stronger. We conjecture that the influence of the object reveals the assumption that similar objects moving at the same speed and in similar directions are perceived to move within the same plane, a plane subject to a fronto-parallel bias.
物体投射阴影的运动轨迹已被证明会改变投射物体的感知轨迹，即使投射阴影看起来不真实，这种效应依然存在。这就引出了一个问题：这种影响是否本身就需要投射阴影，这个问题仅在静止目标的情况下进行过研究。我们使用类似于克斯滕、马马西安和尼尔的盒中球动画的范式，研究了阴影和球形物体对相同球形物体感知运动轨迹的相对影响。我们记录了目标轨迹感知终点的深度和高度估计值，作为各种目标和背景轨迹的函数。阴影和物体都显著影响了目标的感知轨迹，不过阴影的影响总体上更强。我们推测，物体的影响揭示了这样一种假设，即速度相同、方向相似的相似物体被感知为在同一平面内移动，这个平面存在额状面平行偏差。
