Did you know it's possible for scientists to trick your brain into thinking you have an additional appendage?
A participant might stand in front of a mirror placing their left hand in such a way that the thumb doesn’t show. A researcher then strokes the non-thumb side of the left hand at the same time as stroking the side with the thumb. In the space of a few moments, the participant begins to feel as though they have a second thumb on the wrong side of their hand — even though they can clearly see this is not the case .
“Your brain immediately jumps to the conclusion that it has an extra body part,” says Denise Cadete, a neuroscientist at Birkbeck, University of London. “In seconds, you can feel a body part that has a different shape, consistency [and] length.”