Peripheral circular contours inhibit the visual orientation control system.

Peripheral visual stimulation with a tilted luminous frame has long been known to influence both body orientation and the apparent tilt of objects. Peripheral visual inputs along with vestibular and somaesthetic components thus constitute a multi-channel perceptual orientation control system. Surrounding the visual induction pattern with a luminous circle reduced the effectiveness of the visual channel to about 23% of maximum, whereas inscribing a circle within the luminous frame was without effect. This finding suggests a simple method for dealing with undesirable visual-vestibular interactions and an explanation for some instances of disorientation.