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July 26, 2007

New evidence may help explain why we yawn.


A deliberately yawn-inducing study. I’m Bob Hirshon and this is Science Update.

The biological purpose of yawning has eluded scientists for centuries. Now, psychologist Gordon Gallup of the State University of New York at Albany and his son Andrew have found indirect evidence for a promising new theory: that yawning cools off the brain. Gallup explains that our brains require constant cooling in order to function.

GORDON GALLUP (University at Albany):
Brains generate a lot of heat. In fact your brain consumes roughly a third of all of the calories that you take in on a daily basis.

His study found that other proven brain-cooling techniques, like breathing through your nose or putting ice packs on your forehead, can actually suppress yawning – perhaps because they make it unnecessary. Gallup also notes that yawning is a common side effect of diseases and drugs that raise brain temperature. I’m Bob Hirshon, for AAAS, the science society.