To many people who have had an out-of-body experience, they are profoundly spiritual events that reveal how the mind extends beyond the material confines of the body and strengthen beliefs in religion or the paranormal.
The sensation of watching your own body from a distance, however, need owe nothing to the supernatural, research has proved.
Scientists have recreated such out-of-body experiences in the laboratory successfully for the first time, in a pair of experiments that show them to be nothing more than tricks of the mind.
With a combination of virtual-reality goggles and tactile stimulation, researchers in Britain and Switzerland induced volunteers to feel that they have left their bodies to view themselves from a few metres away. The illusion is said to feel as if the subject’s consciousness has been “teleported” elsewhere.
The results could eventually have commercial, medical, scientific and military applications. Similar virtual-reality technology could help surgeons to operate on patients in distant hospitals, and scientists to control hu-manoid robots on the Moon or Mars. Though scientists behind the experiments said they had no ties to military research, the work could be used to improve remote-controlled weaponry.
Henrik Ehrsson, of University College London, who performed one of the two studies published in the journal Science, said they shed important light on the nature of consciousness.
“Out-of-body experiences have fascinated mankind for millennia,” he said. They raised fundamental questions about the relationship between human consciousness and the body, and had been much discussed in theology, philosophy and psychology. “Although out-of-body experiences have been reported in clinical conditions, the neuro-scientific basis of this phenomenon remains unclear.
“The invention of this illusion is important because it reveals the basic mechanism that produces the feeling of being inside the physical body. This represents a significant advance . . . the experience of one’s own body as the centre of awareness is a fundamental aspect of self-consciousness,” Dr Ehrsson said. “If we can project people so they feel and respond as if they were really in a virtual version of themselves, just imagine the implications.”
In his study, volunteers wore goggles, and cameras were placed 2m (6ft) behind the subject, with the feeds connected to the subject’s eyes. The participant thus saw an image of his or her back. Dr Ehrsson stood behind the subject and held two rods. He used one to prod the subject and the other to jab underneath the camera. The participants said they felt they were sitting where the cameras were placed, and that the figure they were watching was another person or a dummy.
“This was a bizarre, fascinating experience for the participants – it felt absolutely real for them and was not scary. Many giggled and said, ‘Wow, this is so weird’.” He said that when he took part, he felt himself move suddenly out of his body. “I see the object coming towards me, feel the touch, then ‘boof!’, I feel a striking sensation that I’m over there looking at myself.”
Out-of-body experiences are often associated with neurological conditions such as migraines and epilepsy, as well as with drug abuse and serious injuries, particularly to the head. They probably come about because the brain is misled by circuits that are not working properly. Dr Ehrsson said: “The brain is always trying to interpret sensory information. If the information is flawed, it can come up with an illusory interpretation.”
In the second experiment, a team at the Ecole Polytechnique Fédérale in Lausanne fitted volunteers with similar goggles, then trained the cameras on a mannequin. The backs of the subject and the mannequin were stroked – though the subject could see only the mannequin. They were blindfolded and moved away, then asked to walk to return to their position. They tended to move towards where they had seen their “virtual bodies”.
Susan Blackmore, of the University of the West of England, said: “Out-of-body experiences should be understood not as evidence for the supernatural, but as a fascinating experience that potentially we can all have.”
Aug. 23, 2007
Mark Henderson, Science Editor