Read about all the tactile and body illusions in our special feature
About 10 years ago, psychologists in Pennsylvania discovered an amazing illusion. They found that they could convince people that a rubber hand was their own by putting it on a table in front of them while stroking it in the same way as their real hand (see box, for a how-to guide).
The now-famous 鈥渞ubber hand illusion鈥� was not only a mind-blowing party trick, it was also hugely important in understanding how sight, touch and 鈥減roprioception鈥� 鈥� the sense of body position 鈥� combine to create a convincing feeling of body ownership, one of the foundations of self-consciousness ().
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In recent years that understanding has been explored further using increasingly freaky illusions. 鈥淭he rubber hand illusion really inspired people,鈥� says , a neuroscientist at the Karolinska Institute in Stockholm, Sweden. He is one of many researchers who have taken the illusion and run with it, creating a whole new set of 鈥渂odily illusions鈥� that mess with our sense of self in strange and disturbing ways. 鈥淲e鈥檙e doing all kinds of crazy stuff,鈥� he says.
The work could have applications in virtual reality, but ultimately, he says, 鈥渨e want to know how the brain represents the body. It鈥檚 a problem of multisensory integration 鈥� your eyes, your skin, your muscles. It is crucial to combine them in the right way to perceive your body. We want to learn how the integration takes place.鈥� Here are a few of the best illusions devised so far.
Read about all the tactile and body illusions in our special feature
How to turn a rubber hand into a 鈥榬eal鈥� one
To experience the rubber hand illusion, you鈥檒l need a fake hand of some kind 鈥� an inflated rubber glove will often do the trick 鈥� a flat piece of cardboard and two small paintbrushes. Place the hand on a table in front of you and conceal your real hand behind the cardboard.
Now get somebody to stroke and tap the fake hand and real hand using identical movements of the paintbrushes. Look at the fake hand for a while until the illusion kicks in.
