Do We Have to Look at the Mirror All the Time? Effect of Partial Visuomotor Feedback on Body Ownership of a Virtual Human Tail

Abstract

Studies have shown that the sense of body ownership towards virtual humanoid avatars with additional body parts can be successfully elicited when synchronous visuomotor and/or visuotactile feedback is given. In an interactive virtual reality (VR) application, however, it is difficult for users to uninterruptedly observe the added body parts, especially when they are attached to the backs of the avatars. Thus, the embodiment of such body parts needs to be achieved using limited synchronous visuomotor feedback. Commonly, it is specifically done by looking at a virtual mirror reflection of the avatar’s movement. However, the methodology of eliciting the sense of body ownership in such conditions remains to be studied. In this paper, we investigate whether it is possible to elicit a sense of body ownership using an avatar with a tail attached to its coccyx, even when the synchronous visuomotor feedback from a mirror is partial (i.e., interrupted or reduced, not a complete asynchrony). In the experiment, participants performed a task under the following three conditions regarding visuomotor synchrony provision: where the feedback is constantly given, given until halfway through the trial (reduction), and interruptedly given (interruption). Results suggest that the interruption or the reduction of the synchronous visuomotor feedback does not significantly disturb the elicitation of body ownership of the virtual tail. Thus, ownership in this fashion can be elicited in a manner insignificantly inferior to that of when synchronous visuomotor feedback is constantly given. Our findings create opportunities for researchers and engineers to more freely design interactive VR applications involving the embodiment of virtual avatars with extra body parts attached.