Endogenous attention prolongs dominance durations in binocular rivalry

Abstract

We investigated the effects of attention on dominance durations during binocular rivalry. In a series of three experiments, observers performed several tasks while viewing rival stimuli to ensure and control deployment of attention. We found that endogenous attention can prolong dominance durations of attended stimulus. We developed a novel single-task procedure where observer's responses in an attentional task were used to objectively estimate dominance durations of the attended stimulus. Using this procedure, we showed that paying attention to the stimulus features involved in rivalry is necessary for prolonging dominance durations--mere engagement of attention during rivalry was insufficient. Finally, we were able to simulate the effects of endogenous attention by doubling the contrast of the attended stimulus while it was dominant. Attention may increase the apparent contrast of the attended stimulus, thereby prolonging its dominance duration. Overall, our results indicate that dominance durations in rivalry can be prolonged when observers are performing an attentionally demanding task on the rival stimulus.

Perceptual training profoundly alters binocular rivalry through both sensory and attentional enhancements

“…As task performance improved, task difficulty was adjusted any time task accuracy within a session exceeded 90% correct. Note that this task can only be performed accurately while the bull's-eye stimulus is dominant, and thus constitutes an objective measure of stimulus dominance (6). The depicted aspect ratio change is exaggerated for illustrative purposes.…”

“…In designing the training paradigm, our starting point was the observation that modest selective modulations of binocular rivalry are found when task-driven attention is directed to the features of the target rival stimulus (5-7, 23, 24). For example, predominance of a rival target increased when observers discriminated subtle changes in its aspect ratio, but did not change when they tracked changes in the background shading overlaid on the top of the same image (6). Here, we used the same aspect ratio tracking task (6) to ensure that observers continuously attended to the target stimulus's features when it was perceptually dominant (Fig.…”

“…For example, predominance of a rival target increased when observers discriminated subtle changes in its aspect ratio, but did not change when they tracked changes in the background shading overlaid on the top of the same image (6). Here, we used the same aspect ratio tracking task (6) to ensure that observers continuously attended to the target stimulus's features when it was perceptually dominant (Fig. 1A).…”

“…1A). Crucially, this yields an objective measurement of rivalry predominance because this task can only be performed accurately when the attended stimulus is perceptually dominant (6). As task performance improved, we increased task difficulty to ensure that the task remained attentionally demanding throughout training.…”

“…Observers who are instructed to "hold" one of the two rival targets dominant exhibit relatively little influence over the dynamics of binocular rivalry (3). Rivalry becomes more susceptible to selective modulation under conditions that promote the deployment of attention to features present in only one of the two rivalry targets (4)(5)(6)(7). However, compared with strong effects of visual attention on perception in other domains (8,9), these effects are modest and suggest additional limiting conditions on attention's ability to influence perception during binocular rivalry (10).…”