retinal rivalry

Retinal rivalry, also known as binocular rivalry, is a phenomenon in psychology and vision science. It occurs when two different images are presented simultaneously to corresponding areas of both eyes. Instead of fusing into a single image, the brain alternates between perceiving one image and then the other. This can result in the perception of one target, then the other, or a mosaic of contours, but not both at the same time.1

This "competition" for attention between the two retinal fields means that a single, unified percept is not always achieved. For example, if one eye sees a vertical bar and the other sees a horizontal bar, the viewer typically perceives only the vertical or only the horizontal bar, with an alternating dominance between them. This phenomenon highlights the complex way our brains process visual information from both eyes to create our perception of the world.2