Inattention abolishes binocular rivalry: perceptual evidence.

Binocular rivalry refers to the unstable perceptual experience that arises when an observer views a different image with each eye: Each image reaches awareness in turn as the other becomes temporarily invisible. Using a novel experimental paradigm, we provide the first direct, perceptual evidence that binocular rivalry occurs only in the presence of attention. Observers in our experiment withdrew attention from a binocular rivalry stimulus shortly after one of the eyes' images was forced to visibility. Seconds later, they shifted attention back to the stimulus to report their perception. For all observers, reported perception strongly and significantly deviated from the results that would be expected if binocular rivalry continued during inattention. Strikingly, reports instead exactly matched those obtained when the stimulus was physically removed for seconds rather than left unattended. These results show that disregarding a binocular rivalry stimulus is equivalent to having it removed from view. Thus, inattention abolishes binocular rivalry.