The effects of proprioceptive and visual feedback on geographical orientation in virtual environments

To effectively use a virtual environment (VE) for applications such as training and design evaluation, a good sense of orientation is needed in the VE. "Natural" human geographical orientation, when moving around in the world, relies on visual as well as proprioceptive feedback. However, the present navigation metaphors that are used to move around in the VE often lack proprioceptive feedback. To investigate the possible consequences this may have, an experiment was conducted on the relative contributions of visual and proprioceptive feedback on path integration in VE. Subjects were immersed in a virtual forest and were asked to turn specific angles under different combinations of visual, vestibular, and kinesthetic feedback (pure visual, visual plus vestibular, visual plus vestibular plus kinesthetic, pure vestibular, and vestibular plus kinesthetic). Furthermore, two visual conditions with different visual flows were tested: normal visual flow and decreased visual flow provided by a 60% zoom. Results show that kinesthetic feedback provides the most reliable and accurate source of information to use for path integration, indicating the benefits of incorporating this kind of feedback in navigation metaphors. Orientation based on visual flow alone is most inaccurate and unreliable. In all conditions, subjects overestimated their turning speed and subsequently didn't turn far enough. Both the absolute errors and the variation in path integration increase with the length of the path.