Enhancement of bistable perception associated with visual stimulus rivalry

Rapid, repetitive exchange of dissimilar, rival stimuli between the two eyes can produce slow alternations in perceptual dominance. This phenomenon, called stimulus rivalry, is potentially important for studying resolution of visual conflict associated with neural processing beyond the level of interocular competition. As previously implemented, however, stimulus rivalry can be difficult for some observers to experience, and it tends to occur within a relatively narrow range of contrasts and spatial frequencies. Here we show that it is possible to increase the incidence of stimulus rivalry by brief, periodic presentation of a composite configuration created by superimposition of the two rival stimuli. Possible reasons for the effectiveness of the composite in promotion of stimulus rivalry are discussed.