Non-human Looking Robot Arms Induce Illusion of Embodiment

We examine whether non-human looking humanoid robot arms can be perceived as part of one's own body. In two subsequent experiments, participants experienced high levels of embodiment of a robotic arm that had a blue end effector with no fingers (Experiment 1) and of a robotic arm that ended with a gripper (Experiment 2) when it was stroked synchronously with the real arm. Levels of embodiment were significantly higher than the corresponding asynchronous condition and similar to those reported for a human-looking arm. Additionally, we found that visuo-movement synchronization also induced embodiment of the robot arm and that embodiment was even partially maintained when the robot hand was covered with a blue plastic cover. We conclude that humans are able to experience a strong sense of embodiment towards non-human looking robot arms. The results have important implications for the domains related to robotic embodiment.