ON ILLUSORY CONTOURS AND THEIR FUNCTIONAL-SIGNIFICANCE

Evidence from neurophysiology and from behavioral studies on non-human vertebrates and invertebrates suggests that the early processing of i llusory contour information relies on adaptive visual mechanisms. The significance of such mechanisms for the survival of various species is about to become an increasingly important issue in our understanding of newly discovered phenomena of visual adaptation and perceptual lear ning. Neurophysiological and computational approaches together with a consistent body of evidence from visual psychophysics have helped to s hed light on the mechanisms underlying contour integration, contour co mpletion, virtual borders, and the perceptual emergence of illusory co ntours. This article reviews some of the major empirical evidence sugg esting a common functional significance of real and illusory contours and then sets out to demonstrate how these functional aspects can be s tudied by finely tuned psychophysical techniques.