Cognitive neuroscientists at the Swedish medical university Karolinska Institutet (KI) have succeeded in making subjects perceive the bodies of mannequins and other people as their own.
The findings are published in the online, open-access journal PLoS ONE, December 3.
In the first experiment, the head of a shop dummy was fitted with two cameras connected to two small screens placed in front of the subjects' eyes, so that they saw what the dummy "saw." When the dummy's camera eyes and a subject's head were directed downwards, the subject saw the dummy's body where he/she would normally have seen his/her own.
The illusion of body-swapping was created when the scientist touched the stomach of both with two sticks. The subject could then see that the mannequin's stomach was being touched while feeling (but not seeing) a similar sensation on his/her own stomach. As a result, the subject developed a powerful sensation that the mannequin's body was his/her own.
"This shows how easy it is to change the brain's perception of the physical self," says Henrik Ehrsson, who led the project. "By manipulating sensory impressions, it's possible to fool the self not only out of its body but into other bodies too."
In another experiment, the camera was mounted onto another person's head. When this person and the subject turned towards each other to shake hands, the subject perceived the camera-wearer's body as his/her own.