The importance of head-free gaze control in humans performing a spatial orientation task

The present study aimed at investigating how a specific instruction concerning gaze orientation, which involved active head motion, could influence the performance of human subjects in a self-controlled whole-body rotation task in the dark. Subjects were seated on a mobile robotic chair that they controlled using a joystick. They were asked to perform 360 degrees rotations while maintaining, when possible, the gaze on the estimated position of an earth-fixed target. Subjects performed better when gazing at this target than when no target was shown. Furthermore, performance was significantly related to head stabilization in space. The results reveal the importance of head-free gaze control for spatial orientation in so far as it may involve spatial reference cues and sensory signals of different modalities, which may be beneficial to self-motion perception.