Young Infants Detect the Direction of Biological Motion in Point-Light Displays

In the present study, we examined if young infants can extract information regarding the directionality of biological motion. We report that 6-month-old infants can differentiate leftward and rightward motions from a movie depicting the sagittal view of an upright human point-light walker, walking as if on a treadmill. Inversion of the stimuli resulted in no detection of directionality. These findings suggest that biological motion displays convey information for young infants beyond that which distinguishes them from nonbiological motion; aspects of the action itself are also detected. The potential visual mechanisms underlying biological motion detection, as well as the behavioral interpretations of point-light figures, are discussed.