Haffenden A M, Goodale M A
Department of Psychology, University of Western Ontario, London, Ontario, N6A 5C2, Canada.
J Cogn Neurosci. 1998 Jan;10(1):122-36. doi: 10.1162/089892998563824.
The present study examined the effect of a size-contrast illusion (Ebbinghaus or Titchener Circles Illusion) on visual perception and the visual control of grasping movements. Seventeen right-handed participants picked up and, on other trials, estimated the size of "poker-chip" disks, which functioned as the target circles in a three-dimensional version of the illusion. In the estimation condition, subjects indicated how big they thought the target was by separating their thumb and forefinger to match the target's size. After initial viewing, no visual feedback from the hand or the target was available. Scaling of grip aperture was found to be strongly correlated with the physical size of the disks, while manual estimations of disk size were biased in the direction of the illusion. Evidently, grip aperture is calibrated to the true size of an object, even when perception of object size is distorted by a pictorial illusion, a result that is consistent with recent suggestions that visually guided prehension and visual perception are mediated by separate visual pathways.
本研究考察了大小对比错觉（埃宾浩斯或铁钦纳圆环错觉）对视觉感知以及抓握动作视觉控制的影响。17名右利手参与者拿起并在其他试验中估计“扑克筹码”圆盘的大小，这些圆盘在三维版本的错觉中充当目标圆。在估计条件下，受试者通过分开拇指和食指以匹配目标大小来表明他们认为目标有多大。在初始观察后，手或目标没有视觉反馈。发现握距缩放与圆盘的实际大小密切相关，而对圆盘大小的手动估计则朝着错觉的方向产生偏差。显然，即使物体大小的感知因图形错觉而扭曲，握距仍会根据物体的真实大小进行校准，这一结果与最近关于视觉引导的抓握和视觉感知由不同视觉通路介导的观点一致。
