Biological motion as a cue for spatial attention: Walking

Abstract

Introduction: Movements of living entities in our environment are an important source of information. Here we explored walking movements as a cue for attention. A recent study reported a point-light walker (PLW) could induce reflexive attentional orienting in the direction it is facing, even when it is task irrelevant (Shi, et al., 2010). Given direction information from PLWs can be extracted without motion (Lange & Lappe, 2006) or from local motion alone (Troje & Westhoff, 2006), we wondered whether the attentional orienting effect was driven by form- or by motion-based processes. Methods: Subjects viewed PLWs that faced left or right that could also walk forward or backward (i.e., PL moonwalkers). A gabor patch was then presented either on the left or the right side of the screen. In Experiment 1, all PLWs were presented centrally and were task irrelevant. In Experiment 2, we presented occasional scrambled "catch" trials requiring subjects to attend the PLWs (even though they still did not cue target locations). We also presented the PLW cues both centrally and peripherally. Results: Experiment 1 failed to replicate Shi et al (2010): There was no evidence of attentional orienting in our data, neither for facing, nor for walking direction. In Experiment 2, where subjects had to attend the PLWs for an unrelated task, subjects were significantly more accurate in responding to targets congruent with the motion direction of the PLW. The effects were found only for central presentation of the PLWs. Conclusions: Reflexive attentional orienting effects induced by a PLW appear to be fickle. When subjects did not attend the PLW, there was no attentional effect. When subjects attended the PLW, we found a significant effect of motion direction, and not facing direction, and only when the PLW was presented centrally. Meeting abstract presented at VSS 2012