Want to teleport through space or travel the world at will? Out-of-body technology can alter your sense of place and set you free.
(Discover Magazine) As you read this story, perhaps you are sitting in a chair in your living room or on an airplane bound for Cancún. Now dig a little deeper, focus inward, and ask yourself this: What is the location of your internal being, your sense of self, that most essential I? Sure, you exist in your body, in your head presumably, itself ensconced someplace particular in the world. But what if all that were secondary? What if your perception could be altered so that you could be anyone and anyplace at all—leaving without traveling?
Those are real possibilities now posed by neuroscientists studying the locus of self- perception in the brain. The research suggests that our concept of self, along with a related quality called presence (the sense of being immersed in a location or environment), need not be tied to our physical bodies. Although most of the current research is still lab-based, scientists have already imbued test participants with the sense of moving from their own bodies into another form, such as a Barbie doll, or watching themselves from a distance in a willful out-of-body experience. The new body-swapping and teleportation techniques illustrate the incredible imaginative potential of the brain and the malleability of perception.
1. RAISE YOUR THIRD HAND
Humans were long assumed to have an unshakable innate body plan, meaning that our brains and hard-wired sense of self could never accept having anything other than one head, two arms, and two legs. But in 1998, University of Pittsburgh psychiatrists Matthew Botvinick and Jonathan Cohen conducted the now-classic “rubber-hand illusion,” which showed the brain could feel ownership of a body part that was not truly its own. In that experiment, a research subject’s real hand was stroked while a prosthetic hand was also stroked in exactly the same way. In less than two minutes, most participants felt that the rubber limb was part of their own body, provided their own hand was hidden while the rubber one stayed in view.
Taking the findings further, cognitive neuroscientist Henrik Ehrsson, who heads the Karolinska Institute’s Brain, Body and Self Laboratory in Stockholm, showed the brain could fully accept ownership of three hands at once. To make his point, he again induced the illusion that his subjects had a third hand but this time threatened either the prosthetic hand or a real one with a kitchen knife. Next he measured the subjects’ degree of sweating, a stress reaction, in 154 test participants and controls. Ehrsson found that people exhibited the same fear-based physiological response regardless of whether a real or fake hand was threatened, suggesting the rubber hand felt almost as authentically their own as their flesh-and-blood appendages.
How could this simple illusion seem so real? By scanning his subjects with functional magnetic resonance imaging (fMRI), Ehrsson found the illusion involves interconnected areas of the brain, including the premotor cortex in the frontal lobe (responsible for sensory guidance of movement) and the intraparietal cortex in the parietal lobe (involved in locating and recognizing body parts). In the nexus of these two regions, neurons take signals from muscles, eyes, ears, skin, and other sensory organs and weave them together to create the experience of the body in space. The brain’s tendency to bind what the eyes see to what the body feels is so powerful that the cues can make a participant take ownership of the rubber limb.
Recently, psychologist Roger Newport of the University of Nottingham in Great Britain showed that the internal self can also be convinced that body parts have changed shape or even disappeared. Instead of working with a static fake hand, Newport developed the Mirage, an illusion-creating box that incorporates a series of mirrors and cameras. Stick your hand in, look through the clear top, and it seems as if you are looking at your real hand. In actuality, you are looking at a real-time video image of your limb that can be manipulated and distorted. The video input can be altered, for instance, to show fingers stretching like putty or telescoping into themselves.
When these images are coupled with unseen, gentle manipulations of the real hand carried out by an investigator, test participants experience their illusory fingers as so real that when their video-manipulated digits appear stretched to cartoonish lengths, they believe they have touched a wooden block that lies far out of reach.
DIY: How to sense a rubber hand
Sit at a table with one hand out of view (you can use a partition made from folded cardboard). Have a friend place a fake hand—a novelty rubber one from a costume store, even an inflated rubber glove—beside your real hand, but in full view. Then have your helper lightly touch your hidden hand with a small brush while simultaneously touching the visible fake hand with identical strokes as you watch. You should soon feel as if the fake hand is yours. Bonus test: After two minutes, close your eyes, then try to point to your real hand. Most people point to the fake one instead.