Unconscious retinotopic motion processing affects non-retinotopic motion perception

Unconscious visual stimuli can affect conscious perception: For example, an invisible prime can affect responses to a subsequent target. The invisible interpretation of an ambiguous figure can have similar effects. Invisibility in these situations is typically explained by stimulus-suppression in early, retinotopic brain areas. We have previously argued that invisibility is closely linked to Gestalt ("object") organization principles. For example, motion is typically perceived in non-retinotopic, object-centered, and not in retinotopic coordinates. Such is the case for a bicycle-reflector that is perceived as circling, although its retinotopic trajectory is cycloidal. Here, we used a modified Ternus-Pikler display in which, just as in everyday vision, the retinotopic motion is invisible and the non-retinotopic motion is perceived. Nevertheless, the invisible retinotopic motion, can strongly degrade the conscious non-retinotopic motion percept. This effect cannot be explained by inhibition at a retinotopic processing stage.