, Volume 68, Issue 5, pp 872-878

Perception of heading without retinal optic flow


How do we determine where we are heading during visually controlled locomotion? Psychophysical research has shown that humans are quite good at judging their travel direction, or heading, from retinal optic flow. Here we show that retinal optic flow is sufficient, but not necessary, for determining heading. By using a purely cyclopean stimulus (random dot cinematogram), we demonstrate heading perception without retinal optic flow. We also show that heading judgments are equally accurate for the cyclopean stimulus and a conventional optic flow stimulus, when the two are matched for motion visibility. The human visual system thus demonstrates flexible, robust use of available visual cues for perceiving heading direction.

This work was supported by Air Force Office of Scientific Research Grant F49620-02-1-0145. A preliminary version of this research was presented at the Vision Sciences Society meeting, May 2003, in Sarasota, Florida.