ILLUSORY, MOTION, AND LUMINANCE-DEFINED CONTOURS INTERACT IN THE HUMAN VISUAL-SYSTEM

Psychophysical studies of interactions between contours defined by dif ferent image attributes report that luminance-defined and illusory con tours show little if any interaction. Because the contours defined by these attributes may vary in perceptual saliency, we employed the tilt aftereffect (TAE) and a cross-adaptation procedure to evaluate intera ction effects between luminance-defined and illusory contours under va rying saliency conditions as well as to explore the interaction betwee n illusory and motion-defined contours. When contour salience of the a daptation or test stimuli was modified by the addition of various amou nts of static noise, we observed a TAE for all combinations of contour types including the novel motion-illusory and illusory-motion pairs. The interactions demonstrated between the contour classes in this as w ell as other studies suggests contour invariance in the orientation do main.