Two scientific teams, from University College London and the Swiss Federal Institute of Technology in Lausanne, managed to recreate the feeling of stepping out of one’s body using a virtual reality system.
In Switzerland, Dr. Olaf Blanke, a neuroscientist at the École Polytechnique FÉdÉrale in Lausanne, asked people to don virtual-reality goggles while standing in an empty room. A camera projected an image of each person taken from the back and displayed that image as if it were six feet in front of the subject, who thus saw an illusory image of himself.
Then Dr. Blanke stroked each person’s back for one minute with a stick while simultaneously projecting the image of the stick onto the illusory body.
When the strokes were synchronous, people reported the sensation of being momentarily within the illusory body. When the strokes were not synchronous, the illusion did not occur.
In another variation, Dr. Blanke projected a “rubber body” – a cheap mannequin bought on eBay and dressed in the same clothes as the subject – into the virtual-reality goggles. With synchronous strokes of the stick, people’s sense of self drifted into the mannequin.
A separate set of experiments was carried out by Henrik Ehrsson, an assistant professor of neuroscience at the Karolinska Institute in Stockholm.
Last year, when Dr. Ehrsson was “a bored medical student at University College London,” he wondered, he said, “what would happen if you ‘took’ your eyes and moved them to a different part of a room.”
“Would you see yourself where your eyes were placed?” he said. “Or from where your body was placed?”
To find out, he asked people to sit in a chair and wear goggles connected to two video cameras placed six feet behind them. The left camera projected to the left eye, the right camera to the right eye. As a result, people saw their own backs from the perspective of a virtual person sitting behind them.
Using two sticks, Dr. Ehrsson stroked each person’s chest for two minutes with one stick while moving the second stick just under the camera lenses, as if it were touching the virtual body.
Again, when the stroking was synchronous, people reported the sense of being outside their own bodies, in this case looking at themselves from a distance where their “eyes” were situated.
Then Dr. Ehrsson grabbed a hammer. While people were experiencing the illusion, he pretended to smash the virtual body by waving the hammer just below the cameras. Immediately, the subjects registered a threat response as measured by sensors on their skin. They sweated, and their pulses raced. They also reacted emotionally, as if they were watching themselves get hurt.
Participants in the experiments conducted by Dr. Blanke and Dr. Ehrsson reported having felt a sense of drifting out of their bodies, but not a strong sense of floating or rotating as is common in full-blown out-of-body experiences, the researchers said.