Shi Zhuanghua, de'Sperati Claudio
Department of Psychologie, Ludwig-Maximilians-Universität München, Munich, Germany.
Cogn Neuropsychol. 2008 Oct-Dec;25(7-8):1027-38. doi: 10.1080/02643290701866051.
When both stationary and moving objects are present in the visual field, localizing objects in space may become difficult, as shown by illusory phenomena such as the Fröhlich effect and the flash-lag effect. Despite the efforts to decipher how motion and position information are combined to form a coherent visual representation, a unitary picture is still lacking. In the flash-lag effect, a flash presented in alignment with a moving stimulus is perceived to lag behind it. We investigated whether this relative spatial localization (i.e., judging the position of the flash relative to that of the moving stimulus) is the result of a linear combination of two absolute localization mechanisms--that is, the coding of the flash position in space and the coding of the position of the moving stimulus in space. In three experiments we showed that (a) the flash is perceived to be shifted in the direction of motion; (b) the moving stimulus is perceived to be ahead of its physical position, the forward shift being larger than that of the flash; (c) the linear combination of these two shifts is quantitatively equivalent to the flash-lag effect, which was measured independently. The results are discussed in relation to perceptual and motor localization mechanisms.
当视野中同时存在静止和运动的物体时，空间中的物体定位可能会变得困难，弗勒利希效应和闪光滞后效应等错觉现象就表明了这一点。尽管人们努力解读运动和位置信息是如何结合形成连贯的视觉表征的，但仍缺乏一个统一的图景。在闪光滞后效应中，与移动刺激对齐呈现的闪光被感知为落在其后。我们研究了这种相对空间定位（即判断闪光相对于移动刺激的位置）是否是两种绝对定位机制线性组合的结果，也就是说，空间中闪光位置的编码和空间中移动刺激位置的编码。在三个实验中，我们表明：（a）闪光被感知为在运动方向上发生了偏移；（b）移动刺激被感知为在其实际位置之前，向前的偏移比闪光的偏移更大；（c）这两种偏移的线性组合在数量上等同于独立测量的闪光滞后效应。我们结合感知和运动定位机制对结果进行了讨论。
