Adequacy of models and sensory stimuli: how does it impact the controllability of systems?

Simulator sickness, an adverse physiological reaction to a simulated driving situation, is often attributed exclusively to sensory conflict or sometimes to postural instability. We postulate that simulator sickness occurrence is a negative effect of poor-or non-controllability of the virtual vehicle that induces badly controlled ego-motion in the virtual scene and uneasiness. We believe that this non-controllability stems from a mismatch between the complexity of the virtual vehicle model and that of the simulator's hardware architecture. The architecture limits the quality of the sensory stimuli that can be provided to the user, which is problematic because of the driver's expectations based on their prior real-life driving experience. We designed and conducted a simple within-participants experiment using a small proof-of-concept system to explore our hypothesis. The experiment consisted of the stabilization of a virtual pendulum's oscillations using a haptic-feedback actuator. Twenty-four participants faced situations where (1) the visual feedback and the dynamic behavior of the simulated pendulum were coherent, and (2) they were mismatched. Our results show a significant effect of training on motor control and task performance; mismatch between visual feedback and dynamic model on motor control, task performance, and participant's discomfort. We interpreted these results as supporting our hypothesis.