Department of Cognitive Science, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
J Exp Psychol Hum Percept Perform. 2011 Oct;37(5):1442-57. doi: 10.1037/a0023510.
The aim of this study was to investigate the perception of possibilities for action (i.e., affordances) that depend on one's movement capabilities, and more specifically, the passability of a shrinking gap between converging obstacles. We introduce a new optical invariant that specifies in intrinsic units the minimum locomotor speed needed to safely pass through a shrinking gap. Detecting this information during self-motion requires recovering the component of the obstacles' local optical expansion attributable to obstacle motion, independent of self-motion. In principle, recovering the obstacle motion component could involve either visual or non-visual self-motion information. We investigated the visual and non-visual contributions in two experiments in which subjects walked through a virtual environment and made judgments about whether it was possible to pass through a shrinking gap. On a small percentage of trials, visual and non-visual self-motion information were independently manipulated by varying the speed with which subjects moved through the virtual environment. Comparisons of judgments on such catch trials with judgments on normal trials revealed both visual and non-visual contributions to the detection of information about minimum walking speed.
本研究旨在探讨依赖于个体运动能力的行动可能性感知（即可供性），具体而言，是探讨在两个障碍物逐渐靠拢的缝隙变窄时的可通过性。我们引入了一个新的光学不变量，它以固有单位指定了安全通过逐渐变窄的缝隙所需的最小运动速度。在自身运动过程中检测到这些信息，需要恢复归因于障碍物运动的障碍物局部光扩展的分量，而与自身运动无关。原则上，恢复障碍物运动分量可能涉及视觉或非视觉自身运动信息。我们在两个实验中研究了视觉和非视觉的贡献，实验中，被试在虚拟环境中行走并对是否能够通过逐渐变窄的缝隙做出判断。在一小部分试验中，通过改变被试在虚拟环境中移动的速度，独立地操纵视觉和非视觉的自身运动信息。与正常试验相比，对这些捕获试验的判断的比较揭示了视觉和非视觉信息对最小步行速度信息的检测都有贡献。
