The role of binocular vision in sensorimotor control

Abstract

Human are adept at avoiding collisions with obstacles in everyday cluttered scenes. Previous studies have uncovered that the visuomotor system accounts for possible obstructions during a reach trajectory, and includes such information into a motor plan to help avoid obstacles. Binocular vision has been shown to provide rich depth information, due to the comparison of images received by each eye. Furthermore, this information has been found to afford advantages during reaching and grasping movements (prehension). However, binocular vision’s impact on obstacle avoidance is not well understood. The current study examined binocular vision’s role in obstacle avoidance by having participants complete a simple reach to pick up a target object. Also examined was added scene complexity, which provides greater depth information, and its impact upon obstacle avoidance and prehension. It was found that whilst viewing condition did not affect prehensile performance significantly, scene complexity did. That is, binocular and monocular performance was similar on the vast majority of kinematic measures assessed. However, both viewing conditions were significantly affected by more obstacle presented in the scene, with reduced movement duration times, deceleration times, and peak velocity profiles. Motion parallax, as a useful monocular cue, was also examined to determine whether it could be used effectively during obstacle avoidance in a cluttered scene, especially when binocular information was unavailable. The results from experiment 1 and 2 suggest this additional depth information available during cluttered scenes may not be of use when the task is difficult. Furthermore, binocular vision may not be as essential in prehension and obstacle avoidance as was previously thought.