It's My Fingers' Fault: Investigating the Effect of Shared Avatar Control on Agency and Responsibility Attribution

Previous studies introduced an avatar body control sharing system known as "virtual co-embodiment," where control over bodily movements and external events, or agency, of a single avatar is shared among multiple individuals. However, how this virtual co-embodiment experience influences users' perception of agency, both explicitly and implicitly, and the extent to which they are willing to take responsibility for successful or failed outcomes, remains an imminent problem. In this research, we addressed this issue using: (1) explicit agency questionnaires, (2) implicit intentional binding (IB) effect, (3) responsibility attribution measured through financial gain/loss distribution, and (4) interview to evaluate this experience where agency over the right hand's fingers was fully transferred to a human partner. Given the distinction between two layers of agency (body agency: control over actions, and external agency: action's effect on external events), we also investigated the impact of sharing only the body-level of agency. In a ball-throwing task involving 24 participants, results showed that sharing body agency over the fingers negatively affected the feeling of having control over both the fingers and the entire right upper limb, as measured by the questionnaire. However, sharing external agency did not significantly diminish the participants' perceived control over the ball-throwing, as indicated by IB. Interestingly, while IB demonstrated that participants felt greater causality for failed ball-throwing attempts, they were reluctant to take responsibility and accept financial penalties. Additionally, responsibility attribution was found to be linked to the participants' personal trait-Locus of Control.