It is an urban science legends that we yawn because we are either bored or our brains are deprived of oxygen. Neither theory has been successfully tested.

But in this week’s Science Times, scientists have reported one plausible physiological explanation for yawning: it helps us thermoregulate. Rodents that were exposed to high temperatures constantly yawned. This yawning was concomitant with fluctuations in core body temperatures.

In humans and other social animals, yawning appears to be socially mediated. I learned this early on in a sleep course I took in college. The professor (and my former undergraduate research adviser), my classmates, and I couldn’t resist the temptation to yawn for about 20 minutes.

Sometimes, even reading the word “yawn” can elicit a **YAWN****. So let’s try an experiment.

YAWN, YAWN, YAWN, YAWN, YAWN, YAWN, YAWN, YAWN, YAWN, YAWN, YAWN, YAWN, YAWN…