Susan Martinez-Conde, director of Barrow Neurological Institute’s Laboratory of Visual Neuroscience, has an article in the Mind Matters Scientific American community blog about experiments in Europe to simulate an out of body experience inside a lab using common electronics and a poking stick.
The experiments were conducted by research teams in the UK (H. Henrik Ehrsson) and Switzerland (Bigna Lenggenhager, Tej Tadi, Thomas Metzinger and Olaf Blanke). The participants wore virtual reality goggles connected to video cameras that filmed the participants’ backs. Thus each participant saw his or her own body from the back.
But this trick alone did not induce an out-of-body experience. (And a good thing too. Otherwise you might have an out-of-body experience every time you check out your own backside in the fitting room at the mall). To complete the illusion, the scientists used two plastic rods to stroke synchronously, for 1 or 2 minutes at a time, the participant’s back and the back of the virtual body. Next, the participants were asked to complete a questionnaire to evaluate their subjective perception of the illusion. Amazingly, they reported feeling as if they were being behind their physical bodies and looking at them from this location. The illusion failed when the stroking was asynchronous.
The results demonstrated that there are two key components to the feeling of being located inside the body. First, visual information from the first-person perspective provides indirect information about the location of one’s body in space. The second factor is the detection of correlated tactile and visual events on the (illusory) body. Such multisensory correlations, together with the first-person visual perspective, determine the perceived location of one’s whole body — even if the correlated tactile and visual events are constrained to a small part of the body.
More at the SciAm’s Mind Matters blog…