No special treatment of independent object motion for heading perception.

How do we judge the direction of self-motion (i.e., heading) in the presence of independent object motion? Previous studies that examined this question confounded the effects of a moving object's speed and its position on heading judgments, and did not examine whether the visual system uses salient nonmotion visual cues (such as color contrast and binocular disparity) to segment a moving object from global optic flow prior to heading estimation. The current study addressed these issues with both behavioral testing and computational modeling. Our results show that the visual system does not treat independent object motion separately for the perception of heading during self-motion. This is surprising because we all can segment a moving object from global optic flow and perceive its scene-relative motion independent of self-motion. Our findings support the claim that the perception of self-motion with independent object motion and the perception of object motion during self-motion are performed by different neural mechanisms.