Monday afternoon, I couldn’t stop yawning. Sure, I was tired – I’ve been writing thousands of words a day on top of endless little bits and pieces of translating that keep dribbling in – but this was unusual. Later that afternoon, I saw this:

Yawning may no longer be a wide open question

Worth a click. I wasn’t aware that yawning was one of the great unsolved problems of science.

A dentist from the University of Maryland School of Dentistry (Gary Hack) and a Princeton postdoc (Andrew Gallup) claim that we don’t yawn because we’re tired, sleepy, or need more oxygen.

No, they say, we yawn in order to cool down our brains.

“The brain is exquisitely sensitive to temperature changes and therefore must be protected from overheating,” the authors write. “Brains, like computers, operate best when they are cool.”

Ah, so that’s my problem. I’m overheating. I knew this word count thing was getting out of hand.

Hack says the sinuses function as a sort of bellows system, fanning cool air into the brain.

Apparently people about to have epileptic seizures or migraines yawn a lot. Hack and Gallup think that yawning could be used as a diagnostic tool to identify dysfunctional body temperature regulation:

Excessive yawning appears to be symptomatic of conditions that increase brain and/or core temperature, such as central nervous system damage and sleep deprivation, says Gallup.

Uh-oh. I’m not overworking, I’m sleep deprived. I knew that. Wait – could I possibly have central nervous system damage? That could explain a lot of things…

Gallup tested his theory on rats, measuring their brain temperatures before, during and after yawning, and found that indeed yawning cooled their brains. One woman suffering from excessive yawning took oral temperature before and after yawning and found that indeed, her brain had cooled off when she yawned.

After receiving that information, the woman reported that methods of behavioral brain cooling provided relief and or postponements of her yawning symptoms.

I sure would like some more info on those “methods of behavioral brain cooling.” Do you think it involves sticking something in your ear?

But don’t panic yet. Most garden-variety yawning probably doesn’t indicate central nervous system damage or the onset of MS. It might just be that you’re adjusting to the seasons.

In another study, Galluop went to Arizona and stopped random pedestrians in the street, showing them pictures of people yawning. As everyone knows, yawning is contagious. He found that more people yawned in the winter months than in the summer, when the outside air temperature was at or above body temperature (98.6 F). His correlation held even when factors like humidity, time spent outdoors and the amount of sleep the night before were taken into account.

The researchers concluded that warmer temperatures provide no relief for overheated brains.

Winter is upon us. Does that mean we’re entering prime brain-use season? Do people think better when it’s cold outside? Should we keep indoor temperatures a few degrees lower in order to boost mental productivity? The study doesn’t give any specific advice.

It also didn’t illuminate the mystery of why yawning is contagious. As I yawned my way through our writing group on Monday, fellow writer Liz started to join in, putting her sinus-operated bellows to work in formidable fashion. I’m not excluding the possibility that her brain needed cooling down, we work hard in our group, but how much of her yawn was a genuine physiological need and how much was she just unconsciously following my good example?

I dug a little deeper and discovered that babies start yawning in the womb at as early as 11 weeks, but it’s not until they reach about 4 years old that yawning becomes contagious. (Autistic kids apparently don’t “catch” yawns like normal kids do, btw.) By mirroring my yawn, Liz was being empathetic, like the good friend she is.

Like contagious laughter and contagious crying, scientists have theorized that contagious yawning is a shared experience that promotes social bonding. [….] “We’re looking at the roots of empathy,” says developmental neurologist Robert Provine of UMBC.  – discovery news

Studies have shown that just looking at the eyes of a yawning person can trigger a yawn, as can reading about yawning or even thinking about it. There is some thought that mirror neurons might be involved.

I can verify that observation. As I’m typing here, my sinuses are bellowsing to beat the band. What I’m hoping is that once I’ve finished the post, my brain will be cooled off dramatically, and I can do some really killer writing. If you haven’t already yawned while reading this gripping post, watch the video below for a tougher test.

Are you yawning yet?

Image: Joseph Ducreux pandiculating; self-portrait ca. 1783, from the Wikipedia entry on Yawning