Abstract
PURPOSE Does binocular rivalry, the alternation in perceptual dominance associated with viewing incompatible monocular images, result from a single, omnibus process? As a point of departure for answering this question, we note that dominance phases among neighboring rival targets may covary when those targets imply global spatial structure, via common color, orientation, or motion. Local zones of rivalry seem to interact spatially to promote grouping and, therefore, global dominance. In our experiments, the global context outside of the region of rivalry was changed during rivalry, to learn whether contextual information alters the ability to detect changes in a suppressed target itself. METHODS One eye viewed an array of disks that appeared to be dimples because of implied shading. One member of this array was engaged in rivalry with a dissimilar target presented to the other eye. While suppressed, the rival dimple reversed contrast polarity on some trials but not on others, and the context dimples were sometimes reversed and sometimes not. RESULTS Reversals were detected only when they occurred rather abruptly; more gradual reversals went undetected. Contrary to expectation, contrast reversals outside the zone of rivalry did not enhance the ability to detect changes within the rivalry zone, but rather interfered. Evidently, the fate of the suppressed stimulus is determined by neural events distinct from those responsible for global organization during dominance. To reconcile diverse findings concerning rivalry, it may be important to distinguish between processes responsible for selection of one eye's input for dominance from processes responsible for the implementation and maintenance of suppression.