Embodiment and task performance in finger reaching of shared and joint hands

Abstract

Virtual co-embodiment is the concept of sharing one avatar body with others and manipulating it as one’s own body. There are two methods of sharing: weighted averaging of multiple operators’ movements (shared body) and dividing body parts and taking charge of them (joint body). In this study, this virtual co-embodiment was applied to hands and fingers, and a reaching task with fingers was performed to compare a shared hand in which two participants manipulate one hand on average, a joint hand in which five fingers are divided and taken charge of, and a solo hand in which one person takes full charge of the hand. The results showed that the sense of body ownership and the sense of agency were similar for the solo hand and the shared hand, and significantly decreased for the joint hand when the task difficulty was higher. Task performance was highest for the shared hand when task difficulty was intermediate, and was lower for the joint hand than for the solo hand when task difficulty was high. These results suggest that the average shared hand might have general advantages over the joint hand.