The visual analysis of bodily motion

Abstract

Abstract Abstract. Does the visual system process human movement differently from object movement? If so, what are the criteria that the visual system uses to discriminate between human and non-human motions? A series of psychophysical studies was conducted to address these questions by examining the conditions under which the visual perception of human and object motions appears to rely on similar and different mechanisms. To determine whether motion integration across space is similar for human and non-human movements, observers viewed moving stimuli through a set of spatially disconnected apertures. Under these conditions, motion integration across space was found to signi1cantly differ for human and object movements as long as the human movement was upright and consistent with normal locomotion. An apparent-motion paradigm was used to investigate motion integration across time. It was found that human and object movements are similarly perceived at brief temporal intervals. However, important differences arise at slower display rates. Finally, recent PET data indicate motor-system activity during the perception of possible, but not impossible, human movements. When considered together, these results support the hypothesis that the visual analysis of human movement does differ from the visual analysis of a wide variety of non-human movements whenever visual motion signals are consistent with an observer’s internal representation of possible human movements.