Abstract
Sensory adaptation is believed to account for several perceptual phenomena, such as Troxler fading, although its role in the disappearance phenomenon of motion-induced blindness (MIB) has been a source of recent controversy. It has been proposed that relatively greater adaptation of stationary targets compared to dynamic moving masks makes the targets more prone to perceptual disappearance, and the finding that MIB rates increase as a function of time lends support to this adaptation account (Gorea & Caetta, 2009, J Vis). Here, we offer a novel test of the adaptation account by focusing on mask coherence. We recently showed that MIB decreases as the motion coherence of the mask increases (Wells, Leber & Sparrow, in press, Perception). This coherence effect could potentially be explained by the adaptation account, since masks with high coherence are more stable and thus more readily adapted, compared to masks with low coherence. That is, conditions with low mask adaptation are comparatively less adapted than the target and should thus yield greater MIB. Critically, the adaptation account predicts that the coherence effect should evolve over time, with little difference in MIB rates between low and high coherence conditions at the beginning of the trial (before adaptation has occurred) and larger differences between these conditions at later points in the trial. To evaluate this prediction, we examined MIB rates across four levels of mask coherence (0%, 33%, 66%, and 100%), dividing the trials into six consecutive 5-second bins. Results showed an interaction between coherence and bin, such that MIB rates in the first bin did not vary across coherence but dramatically diverged between the levels of coherence at the later bins. These results are consistent with the account that adaptation contributes to the phenomenon of MIB.
Meeting abstract presented at VSS 2012