Wearing goggles hooked up to cameras on a mannequin gave the illusion that the mannequin’s body was the subject’s own (Credit: Staffan Larsson)

Ever wanted Arnie’s abs or the legs of Julia Roberts? Maybe you’ll get the chance to make believe they are your own in future, now that the illusion of “body-swapping” has been successfully created in the lab.

Spooky as it sounds, neuroscientists at the Karolinska Institute in Stockholm, Sweden, were able to use simple camera trickery to fool volunteers into perceiving the bodies of both mannequins and other people as their own.

To create the illusion, scientists fitted two CCTV cameras onto the head of a male mannequin, and sent the output from the cameras to two small screens in front of the subject’s eyes. When both the dummy’s and subject’s heads were tilted downwards, the subject saw the dummy’s body where they would normally have seen their own.

When the stomachs of both volunteer and mannequin were stroked simultaneously, the volunteer saw the mannequin’s stomach being touched while feeling the corresponding sensation on their own midriff. After two minutes of this, the subject developed a strong sense that the mannequin’s body was their own.


“It feels like I’m the mannequin,” one volunteer reported. “Wow, this is cool,” said another.

Out-of-body experience

“This shows how easy it is to change the brain’s perception of the physical self,” says Henrik Ehrsson, research leader in the department of clinical neuroscience, who headed the project. “By manipulating sensory impressions, it’s possible to fool the self not only out of its body but into other bodies, too.”

The scientists also mounted the camera onto a second person’s head in order to test whether subjects could perceive someone else’s body as their own. When the two turned to shake each other’s hand, the subject perceived the camera-wearer’s body as their own, giving the sensory impression of shaking hands with themselves.

The strength of the illusion was further demonstrated when the researchers held a knife to the camera-wearer’s arm. By measuring the electrical resistance of the subject’s skin, they could detect that the subject’s emotions were aroused, showing that the subject experienced the knife as a threat to their own body.

Man, woman or table?

Although the illusion was maintained even when the subject was of a different sex to the camera-wearer, it was not possible to fool the subject into identifying with objects such as a box or table.

Nevertheless Kynan Eng, a researcher in neuroinformatics at the University of Zurich, Switzerland, says he suspects that after a stimulus of an appropriate kind and duration, people could “produce measurable ownership responses to any virtual or real object, such as an often-used tool”.

“The potential applications of this research and related work include dealing with psychological body-image disturbances such as anorexia, and stroke rehabilitation,” says Eng, who recently discovered that it is possible to induce someone’s brain to temporarily incorporate a virtual limb into their own body image.

Journal reference: PLoS ONE, DOI: 10.1371/journal.pone.0003832