The cyclopean eye is relevant for predicting visual direction

AbstractWells–Hering’s laws summarize how we process direction and predict that monocular stimuli appear displaced with respect to the viewer, but not with respect to other seen objects [Erkelens, C. J., & van Ee, R. (2002). The role of the cyclopean eye in vision: sometimes inappropriate, always irrelevant. Vision Research 42, 1157–1163] criticized this view and claimed that there is no perceptual displacement of these stimuli. We challenge their claim and improve on shortcomings of past studies. LEDs were monocularly presented to the observers, without their knowledge of which eye was being stimulated. Viewing distance was 9–10 cm; fixation distance was 30 cm. Observers reported the perceived relative and absolute directions of monocular stimuli. Our results are consistent with Wells–Hering’s laws