Vestibular Stimulation Enhances Hand Redirection

We demonstrate how the vestibular system (i.e., the sense of balance) influences the perception of hand position in VR. By exploiting this via galvanic vestibular stimulation (GVS), we can enhance the degree to which we can redirect the user’s hands in VR without them noticing, i.e., raising the detection threshold of hand redirection. Our novel cross-modal illusion relies on the principle that a GVS-induced subtle body sway aligns with the user’s expected body balance during hand redirection. This alignment reduces the sensory conflict between the expected and actual body balance, allowing for a larger hand redirection than would normally be noticed. In our user study, we validated that our approach raises the detection threshold of VR hand redirection by approximately $55 \,\%$ for outward and $45 \,\%$ for inward movements. With this increase, our approach broadens the applicability of hand redirection (e.g., compressing a VR space into an even smaller physical area).