YOUNG INFANTS PERCEPTION OF ILLUSORY CONTOURS IN DYNAMIC DISPLAYS

Ninety-six 4-month-old infants were habituated to one of three compute r-generated displays depicting two rod parts above and below an occlud ing box. In the first display, the surfaces and boundaries of the rod and box were specified by dense surface texture. Their depth segregati on was specified by accretion and deletion of background texture and m otion shear. In the second display, the unity of the rod parts and box , and their depth segregation, were specified only by illusory contour s. In the third display, the boundaries of the rod and box were specif ied by illusory contours, perceptible only via spatiotemporal integrat ion of accretion and deletion of sparse-background-texture elements. I nfants appeared to perceive object unity, and segregate the rod and bo x surfaces, in all three displays, indicating use of illusory contours to perceive bounded surfaces in depth. The results suggest a cognitiv e contribution to perception of some illusory contours, abilities whic h seem to be present by at least 4 months of age.