The role of mask coherence in motion-induced blindness.

Motion-induced blindness (MIB) is the perceived disappearance of a salient target when surrounded by a moving mask. Much research has focused on the role of target characteristics on perceived disappearance by a coherently moving mask. However, we asked a different question: mainly, are there certain characteristics about the mask that can impact disappearance? To address this, we behaviorally tested whether MIB is enhanced or reduced by the property of common fate. In experiments 1, 2, and 3, we systematically manipulated the motion coherence of the mask and measured the amount of target disappearance. Results showed that, as mask coherence increased, perceived target disappearance decreased. This pattern was unaffected by the lifetime of the moving dots, the dot density of the motion stimulus, or the target eccentricity. In experiment 4, we investigated whether the number of motion directions contained in an incoherent mask could account for our findings. Using masks containing 1, 3, and 5 motion directions, we found that disappearance did not increase proportionally to the number of motion directions. We discuss our findings in line with current proposed mechanisms of MIB.