Scientists Convince People Their Hands Are Rocks

No matter how much of a critical thinker you consider yourself, your brain is pretty gullible. With a few minutes and a couple of props, your brain can be convinced that one of your limbs is made of rubber or invisible, or that your whole body is the size of a Barbie doll's. All these illusions depend on your senses of vision and touch interacting. But a new illusion trades sight for sound. By hearing the sound of a hammer striking marble each time it tapped their hands, subjects came to feel that their limbs were made of stone. In the original rubber hand illusion, first published in 1998 by psychologists Matthew Botvinick and Jonathan Cohen, subjects sit with one forearm resting on a table. A little wall blocks the subject's own arm from his or her sight, while a rubber arm just inside the wall is clearly visible. A ...