Smeets J B, Brenner E
Vakgroep Fysiologie, Erasmus Universiteit, Rotterdam, The Netherlands.
J Exp Psychol Hum Percept Perform. 1995 Feb;21(1):19-31. doi: 10.1037//0096-1523.21.1.19.
Ss were presented with spiders running from left to right at various velocities over a structured background. Motion of the background influenced the perceived velocity of the spider: Motion of the background in the opposite direction than the spider increased the perceived velocity. The perceived position of the spider was not influenced by background motion. Ss were asked to hit the spiders as quickly as possible. Fast spiders were hit with a higher velocity than slow spiders. The same effect was found if the spiders only differed in apparent velocity, induced by motion of the background. The trajectory of the hit was not influenced by motion of the background. The authors concluded that although velocity is nothing but the change of position in time, velocity and position are processed independently. Furthermore, these two separately processed sources of information are used in both perception and action.
实验对象观看蜘蛛在有结构的背景上以不同速度从左向右移动。背景的移动影响了蜘蛛的感知速度：背景与蜘蛛移动方向相反时，蜘蛛的感知速度会增加。蜘蛛的感知位置不受背景移动的影响。要求实验对象尽快击打蜘蛛。快速移动的蜘蛛被击打的速度比慢速移动的蜘蛛更高。如果蜘蛛仅在由背景移动引起的表观速度上有所不同，也会发现同样的效果。击打轨迹不受背景移动的影响。作者得出结论，尽管速度只是位置随时间的变化，但速度和位置是独立处理的。此外，这两个分别处理的信息源在感知和行动中都被使用。
