Out-of-body experiences uncovered
24 August 2007
What makes out-of-body experiences happen? Now scientists are beginning to find out as, for the first time, they've re-created out-of-body experiences in healthy volunteers. Antenna finds out more...
This research was published in the journal Science on 24 August 2007.
Image: istockphoto.com/Josh Blake
An out-of-body experience is when someone who is awake sees their own body from the perspective of another person. During such experiences people feel that their sense of awareness is located outside of their physical body too.
Many patients say they've had an out-of-body experience and reports are especially common among those suffering from conditions such as stroke, epilepsy and drug abuse. People who've suffered a traumatic accident, such as a car crash, can also have an out-of-body experience. About 1 in 10 people say they've had one at some point in their lives.
Image: Stock.XCHNG/Carlos Paes
But what's going on during an out-of-body experience?
Now two teams of scientists from University College London (UCL)and the Swiss Federal Institute of Technology in Lausanne have begun to unravel the mystery. They've each worked out how to make healthy volunteers have an out-of-body experience 'artificially'.
How did they do it?
The scientists from UCL used a camera and virtual-reality goggles to create their out-of-body illusion. Volunteers sat in view of, but with their back to, the camera. This picture was then fed through to the goggles so that the volunteers could see their own body sitting in front of them, and see where they were sitting in the room.
Volunteers wore virtual reality goggles throughout the experiment.
Image: Henrik Ehrsson, UCL
To make the illusion complete, the scientists touched each volunteer's actual body with a marker at the same time as moving an identical marker towards the camera. Because the volunteers could 'see' through the eyes of the camera, that's where they felt their physical body was, watching a body belonging to somebody else.
The researchers also tried threatening the 'virtual' body by swinging a hammer towards the camera. The volunteers flinched and started sweating as if their actual body had been threatened, even though they could see their real body unharmed right in front of them.
A volunteer tries out the test. As the marker moves towards the camera, the volunteer feels like it's moving towards him, sitting behind his actual body.
Image: Henrik Ehrsson, UCL
Henrik Ehrsson, who conducted the research at UCL, describes the volunteers' reactions: 'It was a surreal, fascinating experience for the participants - it felt absolutely real for them and wasn't scary. Many of them giggled and said "Wow, this is so weird!"'
Henrik Ehrsson, UCL Institute of Neurology.
Image: UCL
The scientists from Switzerland conducted a similar experiment, but projected 'virtual' versions of the volunteers into their VR goggles. When the volunteers' back was stroked at the same time as the virtual body in front of them, they felt as if they were 'in' the virtual body instead.
Next the researchers blindfolded their volunteers, shifted them around, and then asked them to move towards their original position. But the volunteers couldn't manage it - instead they walked towards where the 'virtual' body would have been.
The volunteers see their virtual body being stroked while being stroked themselves.
Image: M Boyer/Science
So what do these studies tell us about out-of-body experiences?
'These results are really interesting', says Dick Passingham, a brain scientist from Oxford University. 'They show us that what we "see" is very important to our sense of self and where we physically are. We don't seem to have a very good idea of "where" our real body is located, so this can be overridden by strong visual and touch sensations.
Dick Passingham, Department of Experimental Psychology, Oxford University.
Image: Oxford University
'But I'm not sure if these studies can explain what's going on during clinical out-of-body experiences. They could be useful in medical applications such as helping people feel like artificial limbs are their own though. The next step is to look at the different brain regions involved and try and really work out what's going on.'
The findings could be useful in other fields too. 'I'm working on a project where we want to produce a computer-generated body that feels like your own,' says Henrik. 'So you could move a virtual body and feel like it was actually yours.
'This could be used in a variety of applications such as in virtual surgery, where a surgeon controls a robotic hand from outside of the operating room. If you could convince a surgeon it was actually their own hand, they would be able to react in a much faster and more intuitive way.'
