Abstract
Attention directed to one eye can increase the strength of that eye's contribution to perception. It is known that when probe stimuli appear monocularly in bistable paradigms there is a shift in dominance toward the probed eye. This occurs more quickly when subjects simultaneously perform a task where they attend to the probe stimulus. Here, we investigate transient shifts in attention after presentation of an attended probe stimulus during binocular rivalry. We measure eye dominance using continuously reported rivalry percepts. Binocular rivalry stimuli were cross-oriented gratings presented to each eye. Subjects (n=17) used a joystick to report a continuous measure of dominance during rivalry. In the probe task, subjects judged the symmetry of twelve coloured circles surrounding the rivalry stimulus. We tested an "active" condition (subjects performed the probe task) and a "passive" condition (subjects did not perform the probe task). We tested conditions where probe stimuli were presented to the left eye, right eye, and binocularly (a control). Time courses of the continuously reported percepts were aligned to each attentional cue onset and averaged across subjects. From the average time courses, we find that upon monocular presentation of the probe, dominance transiently shifts toward the probed eye during rivalry. However, this shift does not occur when the probe is binocularly presented, nor when no probe is presented at all. This result suggests that attention can modulate eye dominance at the eye specific level.