Visual information from object or surface movement that specifies its relative distance to the observer. Associated with this phenomenon is the kinetic depth effect (KDE) discovered by Wallach and O’Connell (1953). As with other depth cues, it is usually produced in combination with other effects such as motion parallax. When rotating visual information is projected on to a two-dimensional screen, a dynamic three-dimensional illusion can occur. It can also occur with point-light displays of human movements when all that is visible is an array of moving dots. The ability to experience the KDE means that the visual system can resolve the ‘structure from motion‘ problem. In this respect, studies indicate that Infants around 4 to 5 months of age can extract depth-from-motion information (specifically, they are sensitive to between-contour motion information KDE displays, but less so to within-contour motion information in such displays).
See Depth perception, Information, Kinetic occlusion, Motion parallax, Relative distance