A “body-swap” effect that convinces people they inhabit a different body from their own has been induced by scientists for the first time.
The experiment, in which volunteers were tricked into perceiving the bodies of other people or mannequins as their own, offers powerful new insights into how the brain constructs the sense of self. It also promises practical implications for treating body image disorders such as anorexia, for designing robotic technology and remote surgery tools, and even for developing better virtual reality games.The illusion was created with a combination of special goggles and tactile stimulation, which fooled participants into sensing that they had moved into another body. The effect was so powerful that when a tailor’s dummy perceived as a volunteer’s body was threatened with a knife, he or she would exhibit physiological signs of stress, such as increased sweating. Even when the other body was a real person of a different sex or race, subjects said they felt a strong sense of ownership over it. “This shows how easy it is to change the brain’s perception of the physical self,” said Henrik Ehrsson, of the Karolinska Institute in Stockholm, who led the research.
“By manipulating sensory impressions, it’s possible to fool the self. This effect was so strong that people could experience being in another person’s body when facing their own body and shaking hands with it. Our results are of fundamental importance because they identify the perceptual processes that produce the feeling of ownership of one’s body.”