Disentangling visually-driven tactile predictions from multisensory integration in body ownership

The sense of owning one’s body is crucial for distinguishing between internal and external sensory information. Research using bodily illusions shows that this sense relies on the integration of visual, tactile, and proprioceptive signals, but the role of multisensory predictions in body ownership remains less understood. We investigated this question using a modified rubber hand illusion paradigm. Two robotic arms delivered taps to two visible rubber hands while a third tapped the participant’s hidden real hand; one rubber hand received synchronous stimulation and the other varying temporal asynchronies. Visual feedback was manipulated across three conditions: full view of the approaching robotic touch probe and the touch event, occlusion of the approaching probe, or occlusion of the touch event itself. Participants indicated which rubber hand they felt the strongest sense of ownership over. Using a signal detection framework, we examined whether occluding predictive visual feedback affected sensitivity of body ownership judgments to visuotactile synchrony, perceptual bias in the illusion, or both. Our results show that occluding visual feedback of the approaching probe does not affect body ownership sensitivity to visuotactile signals; as long as the touch event is visible or its timing can be inferred from apparent motion, sensitivity remains unchanged. However, perceptual bias was reduced when tactile predictions were disrupted by occluding visual information about the approaching touch probe. These findings clarify how visually driven tactile predictions contribute to body ownership and demonstrate utility of signal detection analysis for dissociating sensitivity and bias in this fundamental aspect of bodily self-perception.