Active head rotations influence thresholds and perceived direction of visual motion

Abstract

Self-motion signals must be accounted for such that an accurate and robust perception of object motion can be maintained. However, research in this area has been focused on translation self-motion, as well as often using passive or simulated self-motion cues. Active-self motion generates additional multi-sensory signals and it is therefore important to understand how we disambiguate motion signals while actively moving. Consequently, this thesis utilised virtual reality technology to examine the influence of active head rotations on visual motion perception, specifically on thresholds for perceiving visual motion, and perceived direction of visual motion. Study 1 compared thresholds for visual motion perception between congruent, incongruent and stationary self-motion conditions. The results indicate thresholds were significantly higher when subjects were turning their head, compared to stationary, though no significant difference was found between congruent and incongruent visual-self motion conditions. These findings contrast with prior research on the advantage of tracking and smooth-pursuit eye movement. Study 2 investigated the influence of active head rotations on perceived motion direction, finding perceived direction was pulled toward the direction of head rotation. This evidence supports the theory that visual-vestibular processing primarily exists to disambiguate confounding effects of self-rotation on visual motion perception. It is recommended that future research incorporate the active and passive generation of vestibular signals to develop a greater understanding of the role of rotational self-motion on visual motion perception.