In science fiction, characters often swap bodies to achieve immortality, pose as someone else, or walk a mile in a loved one's shoes. Now neuroscientists at the Karolinska Institute have found a way to convince subjects that they've swapped bodies with another person. Men become women, humans become mannequins, and the participants are eager to try it again.The research team at the Karolinksa Institute presented their findings today at the annual meeting at the Society for Neuroscience. They provided male and female volunteers with sensory input to convince them that they had switched bodies with another person or a mannequin:
Volunteers experienced the body-swap illusion by receiving simultaneous visual and motor input from another's body. In one experiment, each participant stood across from a male mannequin, and in another experiment volunteers faced a female experimenter. A headset covering participants' eyes displayed a three-dimensional view of the other's visual perspective, transmitted from a small video camera positioned on the mannequin's or the woman's head. In the mannequin situation, an experimenter simultaneously touched the participant's belly and the mannequin's belly with separate probes. So the volunteer felt a poking in the abdomen but saw the poking happen as if he or she were the mannequin. In the real-person situation, participant and experimenter shook hands. Thus, while volunteers felt the sensation of hand shaking, it appeared to them that they were shaking their own hand. After 10 to 12 seconds of abdominal touch or hand-shaking, male and female participants spontaneously had the experience of looking out from the body of the male mannequin or the female experimenter. They literally felt that they were in the mannequin's body getting poked or had embodied the female experimenter and were shaking their own hands.
Neither male nor female participants had any trouble convincing themselves that they had entered the body of the male mannequin. Similarly, when male volunteers were given sensory input from the female experimenter, they readily believed that they had swapped bodies with her. And as surreal as the experience was, presenter Valeria Petkova reported that the subjects were ready for another go:
"Our subjects experienced this illusion as being exciting and strange, and often said that they wanted to come back and try it again."