THE DYNAMIC SPECIFICATION OF SURFACES AND BOUNDARIES

Sequential changes in small separated texture elements can produce per ception of a moving form with continuous boundaries. This process of s patiotemporal boundary formation may exist to provide a robust means o f detecting moving objects that occlude more distant textured surfaces . Whereas most research on spatiotemporal boundary formation has been focused on boundary and shape perception, two experiments are reported here on the perception of surface qualities in spatiotemporal boundar y formation. In experiment 1 a free-report procedure was used to inves tigate whether surface perception can be determined by dynamic informa tion alone, apart from static spatial differences. Results showed that dynamic information was sufficient to determine the appearance of a s urface. This dynamic information may play an important role in other a spects of perception. In experiment 2, it was shown that dynamically s pecifying an extended, opaque surface facilitated edge perception. Imp lications for the relation of boundary and surface perception and for theories of perceptual transparency are discussed.