IF YOU thought you knew your hand鈥� like the back of your hand, you could be disappointed. Our mental image of the size and position of our hands seems not to match with reality.
Instead, our brains have inner representations that perceive the hand as wider than it really is, and with stubbier fingers.
and Patrick Haggard of University College London asked volunteers to point to the tips and bases of the fingers of one hand while it was hidden beneath a board. The researchers used an overhead camera to record the guessed positions, then compared these with the dimensions of the real hand.
Advertisement
On average, volunteers estimated that their hands were two-thirds wider than in reality, and their fingers a third shorter (Proceedings of the National Academy of Sciences, ).
The most accurate representations were of the thumb and index finger. Longo says this is not surprising, since these are the digits with the highest tactile sensitivity, and larger regions of the brain are devoted to their use.
The researchers say the findings may help in understanding the basis of conditions associated with body dysmorphia, such as anorexia nervosa. 鈥淭he distortions we have identified may contribute to this,鈥� Longo says. 鈥淭he brain regions responsible may have undue influence on body image perception.鈥�
Longo hopes to investigate this further by studying perceptions of face, foot and belly size.
