Illusory body-ownership entails automatic compensative movement: for the unified representation between body and action

The sense of body-ownership involves the integration of vision and somatosensation. In the rubber hand illusion (RHI), watching a rubber hand being stroked for a short time synchronously as one's own unseen hand is also stroked causes the observers to attribute the rubber hand to their own body. The RHI may elicit proprioceptive drift: The observers' sense of their own hand's location drifts toward the external proxy hand. The current experiments examined the possibility of observing, not the proprioceptive drift, but the actual drift movement during RHI induction. The participants' hand, located on horizontally movable board, tended to move toward the rubber hand only while they observed synchronous visuo-tactile stimulation. Furthermore, even when the participants' hand was located on a fixed, unmovable board (that is, the conventional RHI paradigm), participants automatically administered the force toward the rubber hand. These findings suggest that since awareness of our own body and action are fundamental to self-consciousness, these components of minimal self are closely related and integrated into one agent with a unified awareness of the body and action.