Exploring minimal requirement for body ownership transfer by brain-computer interface

Operators of a pair of robotic hands report ownership of those hands when they hold an image in their mind of a grasp motion and watch the robot perform it. We present a novel body ownership illusion that is induced by merely watching and controlling a robot's motions through a brain-machine interface. In past studies, body ownership illusions were induced by the correlation of sensory inputs, such as vision, touch, and proprioception. However, in the presented illusion none of these sensations was integrated, except vision. Our results show that the interaction between the motor commands and visual feedback of an intended motion is sufficient to evoke the illusion that non-body limbs are incorporated into a person' s own body. In particular, this work discusses the role of proprioceptive information in the mechanism of agency-driven illusions. We believe that our findings can contribute to the improvement of tele-presence systems in which operators perceive tele-operated robots as themselves.