Philbeck J W, Loomis J M, Beall A C
Department of Psychology, University of California, Santa Barbara 93106-9660, USA.
Percept Psychophys. 1997 May;59(4):601-12. doi: 10.3758/bf03211868.
We provide experimental evidence that perceived location is an invariant in the control of action, by showing that different actions are directed toward a single visually specified location in space (corresponding to the putative perceived location) and that this single location, although specified by a fixed physical target, varies with the availability of information about the distance of that target. Observers in two conditions varying in the availability of egocentric distance cues viewed targets at 1.5, 3.1, or 6.0 m and then attempted to walk to the target with eyes closed using one of three paths; the path was not specified until after vision was occluded. The observers stopped at about the same location regardless of the path taken, providing evidence that action was being controlled by some invariant, ostensibly visually perceived location. That it was indeed perceived location was indicated by the manipulation of information about target distance--the trajectories in the full-cues condition converged near the physical target locations, whereas those in the reduced-cues condition converged at locations consistent with the usual perceptual errors found when distance cues are impoverished.
我们通过以下方式提供实验证据，证明感知位置在动作控制中是一个不变量：表明不同的动作指向空间中一个单一的视觉指定位置（对应于假定的感知位置），并且这个单一位置虽然由一个固定的物理目标指定，但会随着关于该目标距离的信息可用性而变化。在自我中心距离线索可用性不同的两种条件下，观察者观察1.5米、3.1米或6.0米处的目标，然后闭上眼睛，使用三条路径之一试图走向目标；路径直到视觉被遮挡后才指定。无论选择哪条路径，观察者都在大致相同的位置停下，这提供了证据表明动作是由某个不变量控制的，表面上是视觉感知位置。通过操纵关于目标距离的信息表明，这确实是感知位置——全线索条件下的轨迹在物理目标位置附近汇聚，而减少线索条件下的轨迹在与距离线索匮乏时通常发现的感知误差一致的位置汇聚。
