Predisposition to out-of-body experience (OBE) is associated with aberrations in multisensory integration : psychophysiological support from a “Rubber-hand Illusion” Study

It has been argued that disorders in body-ownership and aberrant experiences in self-consciousness are due to biases in multisensory integration. Here we examine whether such biases are also associated with spontaneous Out-of-Body Experiences (OBEs) in a non-clinical population. One-hundred and eighty participants took part in a rubber-hand illusion (RHI) experiment with synchronous and asynchronous visual and tactile stimulation. A realistic threat was delivered to the rubber-hand after a fixed period of stimulation. Self-report exit questionnaires measured the subjective strength of the illusion and psychophysiological measures (skin conductance responses / finger temperature) provided an objective index of fear / anxiety towards the threat. Control participants reported a stronger RHI, and revealed larger threat-related skin conductance responses during synchronous compared with asynchronous brushing. For participants predisposed to OBEs, the magnitude of the skin conductance was not influenced by brushing synchrony - fear responses were just as strong in the asynchronous condition as they were in the synchronous condition. There were also no reliable effects of finger-temperature for either group. Collectively, these findings are taken as support for the presence of particular biases in multisensory integration (perhaps via predictive coding mechanisms) in which imprecise top-down tuning occurs resulting in aberrant experiences in self-consciousness even in non-clinical hallucinators