Heartbeats can be used to trigger a weird "out-of-body" experience that may be helpful in the treatment of anorexia, research has shown.
Volunteers were made to feel as if they inhabited an image of their own body two metres away from where they were actually standing.
The trick was to synchronise a flashing bright outline surrounding the virtual image with participants' heartbeat, in real time.
This caused the volunteers to become strongly identified with their body double. Not only did the they perceive the image as "real" but they felt located in a different place, closer to the virtual body than the physical one. Volunteers also experienced the sensation of touch some distance away from their physical body.
Study leader Dr Jane Aspell, senior lecturer in psychology at Anglia Ruskin University in Cambridge, said: "This research demonstrates that the experience of one's self can be altered when presented with information about the internal state of one's body, such as a heartbeat.
"This is compatible with the theory that the brain generates our experience of self by merging information about our body from multiple sources including the eyes, the skin, the ears and even one's internal organs."
Dr Aspell hopes the research, published in the journal Psychological Science, may help people with psychological problems involving distorted self-perception such as anorexia nervosa and body dysmorphic disorder.
She is now working on a study of how the self perception of "yo-yo" dieters changes as they gain and lose weight.
"Patients with anorexia, for example, have a disconnection from their own body. They look in the mirror and think they are larger than they actually are. This may be because their brain does not update its representation of the body after losing weight, and the patient is therefore stuck with a perception of a larger self that is out of date," said Dr Aspell.
"This experiment could be adapted to help people 'reconnect' with their current physical appearance. It could help them realise what the 'real me' actually looks like."