Abstract
A succession of uncorrelated anti-Glass Patterns, composed by dot pairs with opposite luminance polarity, elicits a clear perception of motion in the direction of the white dot of the pair. This effect is due to a delayed perception of black dots with respect to whites (Del Viva et al., VSS 2004). Given the real motion information carried by anti-glass patterns, here we compared it to real motion perception. We measured coherence sensitivities to both stimuli by manipulating several parameters (luminance, dot distance, duration) and found the same behavior in real motion and anti-glass patterns. We also found that motion induced by anti-glass patterns annuls real motion, presented simultaneously in the same display but moving in opposite direction, when the coherence of the two stimuli is comparable. By lowering contrast of one of them, motion toward the stimulus with higher contrast prevails. This suggests that, like real motion (Morrone et al., Nature 1995), anti-glass pattern are processed at two different stages: the first contrast dependent and the second motion dependent. Our data indicate also that anti-glass patterns and real motion interact at low level, suggesting similar mechanisms of analysis.