Researchers Trick Brain into Accepting Third ArmResearchers Trick Brain into Accepting Third Arm

As detailed by Scientific American and The New York Times, researchers had each subject sit and place their hands flat on a table, with a fake right hand positioned next to the real one and a cloth cover making it look like all three hands were natural. When researchers stroked each right hand with a brush, some subjects reported feeling as if they had two right hands. When researchers threatened the fake right hand with a knife, some subjects flinched and had the same physiological reaction they would if a real hand was being threatened. 

According to the researchers, the results, which were published in PloS ONE, an online scientific journal, suggest that the brain may be capable of shifting its perception of the body on the fly, solving the conflict of having two right hands by accepting an asymmetrical set of arms.

There are, of course, possible implications for the advancement of prosthetics. As one of the researchers, Arvid Guterstam, told The Times:

“This might have important bearing on the development of advanced prostheses, where the patient can experience and control an extra robotic arm. Such prosthesis might be five or 10 years in the future, but our research is at least demonstrating that this is not an impossible idea.”

Scientific American even went so far as to posit the idea that fully healthy people might be able to one day add an extra arm or two, which means that the producers of the fourth or fifth Spiderman reboot should be able to save some money on the CGI budget.

— Thomas Blair