Voluntary blinks and eye-widenings, but not spontaneous blinks, facilitate perceptual alternation during continuous flash suppression.

The fact that blinks occur more often than necessary for ocular lubrication has led to the proposal that blinks are involved in altering some aspects of visual cognition. Previous studies have suggested that blinking can modulate the alternation of different visual interpretations of the same stimulus, that is, perceptual alternation in multistable perception. This study investigated whether and how different types of blinks, spontaneous and voluntary, interact with perceptual alternation in a multistable perception paradigm called continuous flash suppression. The results showed that voluntary blinking facilitated perceptual alternation, whereas spontaneous blinking did not. Moreover, voluntary eye-widening, as well as eyelid closing, facilitated perceptual alternation. Physical blackouts, which had timing and duration comparable to those of voluntary blinks, did not produce facilitatory effects. These findings suggest that the effects of voluntary eyelid movements are mediated by extraretinal processes and are consistent with previous findings that different types of blinks are at least partially mediated by different neurophysiological processes. Furthermore, perceptual alternation was also found to facilitate spontaneous blinking. These results indicate that eyelid movements and perceptual alternation interact reciprocally with each other.