Abstract
Previously we found that a physiological signature of binocular rivalry disappeared when attention was diverted away from the competing stimuli (Zhang et al., 2011). However, the perceptual status of the dichoptic stimuli in the unattended condition remains elusive. In the present study, we used a novel behavioral paradigm to investigate the perceptual status of dichoptic stimuli in both the unattended and crowded situation. At the beginning of each trial, a pair of orthogonal gratings was dichoptically presented 2.5 degrees below the fixation, and subjects pressed a button as soon as one of the stimuli became exclusively dominant. Then the dichoptic stimuli were crowded by a set of 4 binocular flankers and subjects started performing a demanding RSVP task at fixation. When the RSVP task stopped, the flankers were removed and the dichoptic gratings remained on the screen for anther 200ms for subjects to report their perceptual status. Compared to the attended condition during which subjects attended to the dichoptic stimuli without flankers, subjects reported much more mixture (patchy) perception in the unattended condition. In a second experiment with no fixation task, subjects directed their attention to the crowded display with the dichoptic stimuli centered at 4 degrees below the fixation. Similarly, in each trial subjects pressed a button to indicate the one of the stimuli was exclusively dominant, and the binocular flankers were immediately added. Following a fixed amount of time, the flankers were removed with the dichoptic stimuli stayed on screen for another 200ms. Subjects again reported more mixture perception compared to the no flanker condition. These results suggest that exclusive rivalry could not be maintained when attention is prevented from reaching the dichoptic stimuli.
Meeting abstract presented at VSS 2012