Audio visual stimuli based out of body illusion

Previous studies have reported that bodily self-consciousness could be altered so that one's body was perceived in extra-personal space. However, whether this could be induced without tactile stimuli has not been investigated. We investigated whether out-of-body illusion could be induced via synchronized audio-visual stimuli, in which auditory stimuli were used instead of tactile stimuli. We conducted an experiment in which a sounding bell was moved in front of the participant, and synchronously, a non-sounding bell was moved in front of a camera that captured the image and projected on a head-mounted device. We expected the participants to experience that the sound came from the non-sounding bell in the video and they were in the camera's position. Results from the questionnaires conducted after the experiment revealed that items related to out-of-body illusion were significantly enhanced in the synchronized conditions. Furthermore, participants reported a similarly strong out-of-body illusion for both the synchronized audio-visual and tactile-visual stimuli. This study demonstrated that out-of-body illusion could also be induced by synchronized audio-visual stimuli, which was a novel finding.