Is movement perception color blind?

Abstract

Our visual environment is usually full of motion. Unquestionably, the perception of movements and spatial relationships of objects is of considerable biological importance. Motion information is also important for decomposing the retinal image into discrete objects (Egure-ground separation), and for the recovety of their three-dimensional shapes (structure from motion). Furthermore, gaze-holding eye movements that compensate for the organism’s own motion or for motion of the observed object rely greatly on visual motion signals. It is hardly surprising, therefore, that biological visual systems have speciakzecl, directionally sensitive motion-detecting neurons. In primates, several cortical areas seem ro be largely devoted to visual motion analysis. We now know from both psychophysical and physiological experiments that motion perception is not merely a convolution of our spatial and temporal perception but represents a fundamental visual dimension as do color or stereoscopic vision 111. Unlike color and stereoscopic vision, however, the capacity to perceive motion appears very early phylogenetically and is found in all animals, including those that lack color or bmocular vision.