Suppression of apparent movement during binocular rivalry

Abstract

STEREOSCOPIC depth perception can coexist with binocular rivalry of form and colour^1–3. If a stereogram is viewed with a red filter in front of one eye and a green filter in front of the other eye (or with an oblique grating superimposed on one eye's picture and an orthogonal grating on the other picture), then stereopsis can still be obtained in spite of the two eyes' pictures being seen alternately rather than simultaneously. Although one image is ‘suppressed’ in consciousness, information about its position is preserved and used for stereopsis. This finding implies either that stereoscopic depth perception ‘precedes’ the site of binocular rivalry in the visual system or that conscious perception and stereopsis are independent visual functions mediated in ‘parallel’ neural channels. Here I consider the related question of whether an image that is suppressed during binocular rivalry (and is, therefore, not ‘seen’ by the observer) can contribute to the perception of apparent movement.