Mirror, Mirror on the Wall…

A new study shows that you may not know the back of your hand just as well as you think. Scientists have recently found that the human brain contains highly distorted perceptions of the size and shape of our hands. The study, which was performed at University College London, found that most people perceive their hands to be shorter and fatter than they really are.

The work could be a link to how the brain subconsciously views other parts of the body and may explain the underlying causes of certain eating disorders. Scientists at University College London asked more than 100 volunteers to place their left hand face-down on a table and cover it with a board. They then asked the volunteers to indicate on the board where they thought the knuckles and fingertips were located.

The results, which were published in the Proceedings of the National Academy of Sciences, showed a consistent overestimation of the width of the hand. A large number of the volunteers estimated their hand to be 80% broader than it really was. According to Matthew Longo of UCL’s Institute of Cognitive Neuroscience, the volunteers also judged their finger lengths to be up to 30-40% shorter than they really were

“Previously it has been assumed that the brain uses a perfectly accurate model of the body and it’s not mysterious where that might come from,” said Longo. “We see our body all the time and it wouldn’t be surprising if the brain had developed an accurate representation of the body.”

The study shows that the brain’s internal measurements can be drastically distorted. Even though the study was carried out specifically on the hand, the results may be applicable to the brain’s perception of the whole body. If this is indeed true, there may be an explanation for certain psychiatric conditions involving body image such as anorexia nervosa or bulimia.

What’s surprising about the findings is that it comes from technically healthy subjects. Mia Holland, chair person of the counseling studies department at Capella University, explains that there are similar methods found in this study that are used during treatment of patients with eating disorders. Counselors will sometimes ask patients with anorexia nervosa to draw a life-size outline of their body. When they are finished, someone will trace the outline of the patient over their original self-portrait. “A size 4 might draw herself as a size 14,” Holland says.

So the next time you look in the mirror and see yourself as too short or too fat, cut yourself some slack. It’s most likely all in your head.

To Your Health & Beauty,
Dr. Kent Hasen

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