The ability to discriminate between different directions and speeds of motion of visual stimuli, as well as those provided by proprioceptive and vestibular inputs. The visual system infers motion from changing patterns of light in the retinal image, but something that has proved difficult to explain in terms of neural mechanisms and processes, or by means of computational models. Some attempt has been made to account for the neural mechanisms of self-motion (heading) perception, with cortical substrates proposed to include the medial superior temporal area and the ventral intraparietal area as well as a complex input of auditory, tactile and vestibular signals. Studies on the development of motion perception in infancy have delivered some fairly consistent findings even though it is not been a major topic of research. Behaviorally, it seems that the ability to detect slow motion improves gradually across the age range of 1 to 3 months whereas that for rapid motion is almost at the adult functional level shortly after birth. In terms of biological motion, it has been reported that 6 month-old infants can distinguish between leftward and rightward motion displayed on a video clip depicting an upright human point-light walker seemingly walking on a treadmill as seen from a sagittal viewpoint (with inversion of the stimuli resulting in no detection of directionality).
See Biological motion, Motion parallax, Perception, Point-light display