Paths of Apparent Human Motion Follow Motor Constraints
The phenomenon of apparent motion, or the illusory perception of movement from rapidly displayed static images, provides an excellent platform for the study of how perceptual systems analyze input over time and space. Studies of the human body in apparent motion further suggest that the visual system is also influenced by an observer’s motor experience with his or her own body. As a result, the human visual system sometimes processes human movement differently from object movement. For example, under apparent motion conditions in which inanimate objects appear to traverse the shortest possible paths of motion, human motion instead appears to follow longer, biomechanically plausible paths of motion. Psychophysical and brain imaging studies converge in supporting the hypothesis that the visual analysis of human movement differs from the visual analysis of nonhuman movements whenever visual motion cues are consistent with an observer’s motor repertoire of possible human actions.