Effect of a disparity pattern on the perception of direction: non-retinal information masks retinal information.

The direction of an object can theoretically be determined from the binocular disparity information alone. However, there is no certain empirical evidence for this. This study examines whether the binocular disparity information alters the perceived direction. Observers make an effort to rotate their eyes beyond their movable limit for a while before observing the display. This is done to alter the reliability of the eye position signal from proprioception and efference copy. The results show that the perceived direction changes according to the amount of disparity information in the stimulus.