Infoscience

Conference paper

Retinotopic information is rendered invisible by non-retinotopic processing

Classically, stimuli are rendered unconscious by backward masking or binocular rivalry, where it is usually assumed that the mask or the stimulus in the contralateral eye suppress the target. Based, on the Ternus-Pikler display (http://lpsy.epfl.ch/research/retino/), we present a new method to render stimuli invisible. We presented a black disk with a white dot on it. From frame to frame, the dot changed its position on a circular orbit creating an apparent motion percept of an either clockwise or counterclockwise rotation. Observers discriminated the rotation direction well with about 93% correct responses. The rotation is perceived in retinotopic coordinates. Next, we added a disk, also with a white dot, alternating to the left and right from frame to frame. The disks themselves, now, appear to jump back and forth in tandem. This ‘‘group motion’’ percept of the Ternus-Pikler disks, in turn leads to a non-retinotopic motion percept for the white dot, which renders the retinotopic rotation invisible (54% correct). When the contextual disk was removed, the original retinotopic motion percept for the white dot was immediately perceived. Hence, by adding contextual elements we can switch between different conscious percepts.

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