Ever wanted Arnie鈥檚 abs or the legs of Julia Roberts? Maybe you鈥檒l get the chance to make believe they are your own in future, now that the illusion of 鈥渂ody-swapping鈥� has been successfully created in the lab.
Spooky as it sounds, neuroscientists at the 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鈥檚 eyes. When both the dummy鈥檚 and subject鈥檚 heads were tilted downwards, the subject saw the dummy鈥檚 body where they would normally have seen their own.
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When the stomachs of both volunteer and mannequin were stroked simultaneously, the volunteer saw the mannequin鈥檚 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鈥檚 body was their own.
鈥淚t feels like I鈥檓 the mannequin,鈥� one volunteer reported. 鈥淲ow, this is cool,鈥� said another.
Out-of-body experience
鈥淭his shows how easy it is to change the brain鈥檚 perception of the physical self,鈥� says , research leader in the department of clinical neuroscience, who headed the project. 鈥淏y manipulating sensory impressions, it鈥檚 possible to fool the self not only out of its body but into other bodies, too.鈥�
The scientists also mounted the camera onto a second person鈥檚 head in order to test whether subjects could perceive someone else鈥檚 body as their own. When the two turned to shake each other鈥檚 hand, the subject perceived the camera-wearer鈥檚 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鈥檚 arm. By , they could detect that the subject鈥檚 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 , 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 鈥減roduce measurable ownership responses to any virtual or real object, such as an often-used tool鈥�.
鈥淭he potential applications of this research and related work include dealing with psychological body-image disturbances such as anorexia, and stroke rehabilitation,鈥� says Eng, who recently discovered that it is possible to induce someone鈥檚 brain to temporarily incorporate a virtual limb into their own body image.
Journal reference: PLoS ONE, DOI:
