A neuroscientist working at University College London is the first to successfully induce an “out-of-body experience” in healthy participants. In a paper published in Science, Dr Henrik Ehrsson, UCL Institute of Neurology, revealed the unique method by which the illusion is created and the implications for the future.
An out-of-body experience (OBE) is defined as the experience in which a person who is awake sees his or her own body from a location outside the physical body. OBEs have been reported in clinical conditions where brain function is compromised, such as stroke, epilepsy and drug abuse. They have also been reported in association with traumatic experiences such as car accidents. Around one in ten people claim to have had an OBE at some time in their lives.
"Out-of-body experiences have fascinated mankind for millennia. Their existence has raised fundamental questions about the relationship between human consciousness and the body, and has been much discussed in theology, philosophy and psychology. Although out-of-body experiences have been reported in a number of clinical conditions, the neuro-scientific basis of this phenomenon remains unclear,” says Ehrsson.
For the study, participant sat in a chair wearing a pair of head-mounted video displays. These had two small screens over each eye, which showed a live film recorded by two video cameras placed beside each other two meters behind the participant's head. The image from the left video camera is presented on the left-eye display and the image from the right camera on the right-eye display. The participant sees these as one 'stereoscopic' (3D) image, so they see their own back displayed from the perspective of someone sitting behind them.
The researcher then stands just beside the participant (in their view) and uses two plastic rods to simultaneously touch the participant's actual chest out-of-view and the chest of the illusory body, moving this second rod towards where the illusory chest would be located, just below the camera's view.
The participants confirmed that they experienced sitting behind their physical body and looking at it from that location. Ehrsson said: "This was a bizarre, fascinating experience for the participants—it felt absolutely real for them and was not scary. Many of them giggled and said 'Wow, this is so weird!'“
To test the illusion further and provide objective evidence, Ehrsson also performed additional experiments to measure the participants' physiological response. In a scenario where the students felt their illusory body was threatened, their physiological response indicated that they experienced the virtual threat as real. One can imagine how such an application could really intensify a role-playing video game.
The creation of this perceptual illusion stems from an idea Ehrsson had as a medical student, when he wondered what would happen to the 'self' if you could effectively move your eyes to another part of the room, just a few meters away, so you could observe yourself from an outside perspective. Would the self 'follow' the eyes or stay in the body"
Dr. Ehrsson points out, "the illusion is different from anything published previously. It is the first to involve a change in the perceived location of the self, relative to the physical body…there has been no way of inducing an OBE in healthy people before, apart from unsubstantiated reports in occult literature. It's a very exciting development, and has implications for a range of disciplines from neuroscience to theology.
"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 because the experience of one's own body as the center of awareness is a fundamental aspect of self-consciousness," said Dr Ehrsson.
This discovery could lead to a variety of industrial applications, says Ehrsson.
"This is essentially a means of projecting yourself, a form of teleportation. If we can project people into a virtual character, so they feel and respond as if they were really in a virtual version of themselves, just imagine the implications. The experience of playing video games could reach a whole new level, but it could go much beyond that. For example, a surgeon could perform remote surgery, by controlling their virtual self from a different location."
Posted by Rebecca Sato
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