The researchers propose to investigate, for the first time, the effects of attention on signal processing during binocular rivalry. Rivalry occurs when two dissimilar images are presented to corresponding regions of the eyes, resulting in an alternation between awareness (dominance) of each of the images. With standard binocular vision, attention has been shown to increase contrast sensitivity, improve spatial resolution, accelerate information accrual, and produce changes in appearance. During binocular rivalry, attention has been shown to influence which of the rivaling images is dominant (perceived) and which is suppressed. Performance will be assessed in a discrimination task by presenting attention cues and stimuli to all nine combinations of the eyes (cue & stimulus in dominant, suppressed, or both eyes). This will allow the researchers to evaluate whether attentional effects occur before or after a shared cortical representation is formed in the visual stream. Using binocular rivalry as a tool, this novel investigation combines two exciting lines of research to discern the locus of attentional effects on signal processing. ? ?