Abstract
Whereas neurophysiological studies have shown that illusory contours are signaled in early visual areas at very short latencies, it has been concluded from behavioral studies using backward masking that illusory-contour stimuli have to be present unmasked for at least 100 ms to be perceived and discriminated. In three experiments, we employed a response-priming paradigm where participants responded to the shape or orientation of illusory and real-contour targets preceded by illusory and real-contour primes at stimulus-onset asynchronies up to 129 ms. Participants either responded to the illusory contours or to the real-contour inducing lines. Priming effects were similar for illusory and real contours, and also across contour type. The effect was fully present in the fastest responses. We conclude that illusory contours can rapidly trigger associated motor responses even under conditions of heavy masking, suggesting that illusory contours are extracted during the first wave of processing traversing the visuomotor system.
German Research Foundation.