belly.jpg Credit: Xenia

Wanna lose three inches from your waist? Forget 8 Second Abs, 6 Second Abs or even, well, 5 Second Abs. Now there's 3 Second Abs, a new program developed by scientists to help you shed extra holiday weight—fast.

Unfortunately, there are no operators standing by to take your credit card information. This isn't an exercise regimen as much as a laboratory trick. But it's one that's helping scientists understand how the brain processes body size and shape, i.e., body image.

The magician here is Henrik Ehrsson, clinical research fellow at University College London. He's the lead author of a study published in the December, 2005 issue of PLoS Biology, in which scientists fooled subjects into believing their waists were shrinking by using a psychophysical technique called the "Pinocchio illusion."

Advertisement

"If you vibrate the muscle—say in the wrist or the biceps—you will elicit an illusory movement," said Ehrsson, explaining the basics of the trick. "Participants will experience that the hand is moving or that the arm is moving."

And if your hand is touching another body part, your brain will tell you that the body part is growing or shrinking to match the false hand movement. For instance, if your wrist is vibrating when you touch your nose, you'll think your nose is elongating (hence the reference to Pinocchio).

"We thought that the illusion was a unique tool to change people's body image in the laboratory," said Ehrsson. "We were interested in testing the idea that body image is constructed in the parietal cortex."

In his experiment, Ehrsson asked subjects to put their hands on their waists while their wrists' tendons were vibrated. The participants reported an average apparent waist shrinkage of about three inches within about three seconds.

The researchers observed the patients using fMRI and found that, indeed, the perception of body size and shape involves higher-order somatosensory areas in the parietal cortex, the part of the brain involved in assessing contextual environments. In keeping with that finding, patients who experienced the strongest illusion showed the strongest activity in the parietal cortex.

Ehrsson said the research could be used to understand how brain injuries affect self-image. He's may also expand the research to study patients with anorexia or other eating disorders involving an overestimation of body size.

The bottom-line: If your sweetie is analyzing herself in the mirror with her hips on her waist and asks, "Do I look fat?," forget about answering with anything related to the parietal cortex. The only answer you need to give is, "No." Even science can't answer that question for you.

, written by Adnaan Wasey, posted on December 1, 2005 06:17 PM, is in the category Brain & Behavior.