What Does “Biological Motion” Really Mean?

Abstract

Abstract For several decades, vision researchers’ use of the term “biological motion” has been used to refer to different things, including the category of all animal movements, the category of all human movements, and, most specifically, the category of human movements depicted in point-light displays. In reviewing data from psychophysical and neurophysiological studies, along with some new perceptual findings, this chapter examines the hypothesis that the visual analysis of human motion does not represent a uniform or bounded perceptual category but rather that analyses of human motion differ in a graded fashion from analyses of nonhuman animal motion. Thus, “biological motion” perception likely defines the perceptual category of human and animal motions organized such that human motion, or, more specifically, the observer’s own motor repertoire, constitutes the prototypical stimulus within the category.