I haven't found out why, but it's so funny how just reading about yawning makes me yawn! You try!
A yawn can be more contagious than the flu. But why?
by Kate Robertson
Bored in a board meeting? Try this: yawn. Then count how many people follow suit. You may be surprised at how many do. A yawn is so contagious, just thinking about a yawn triggers one for me. Writing this column elicited no less than 50 yawns. Why?
I asked my fiance, Kevin, who pondered the problem for a brief moment and then expounded this wisdom: "You yawn because you're running low on oxygen and need a deep breath of air. So when you yawn, you suck oxygen out of the air around you, lowering the overall oxygen level in the room and triggering people around you to yawn.
Yeah, yeah, yeah. Yawn.
First of all, what is a yawn? It starts with an odd urge, similar in its familiarity and undeniability to the urge to sneeze. The mouth stretches wide open, pulling on the facial muscles, causing our eyes to squint and usually tear. At the same time, we suck in a deep breath of air, hold it for just a moment, and then exhale. So a yawn is a reflect action that forces us to take a face-stretching, eye-watering deep breath.
There are several theories about why we yawn. Most have to do with the brain subconsciously registering a reduced level of oxygen in the blood stream, often brought on by shallow breathing that accompanies long, boring meetings, fatigue and stuffy rooms. We yawn to force ourselves to take a deep breath.
A similar theory says we yawn to expel excess carbon dioxide. Again, shallow breathing creates a need to get rid of the stagnant air at the bottom of our lungs. Another theory is that yawning helps redistribute naturally occurring phlegm around the tiny air sacs inside the lungs.
And finally, there's this obscure and unsubstantiated theory: A yawn is like an oil change for the brain. The theory goes that the face-stretching, rib-widening effects of a yawn momentarily increase the pressure of the fluid around the brain. That forces the fluid to be absorbed more rapidly, which triggers an increase in the production of new, cleaner brain fluid.
OK, so the bottom line is we don't really know why we yawn. But no matter. There are still theories about why they are contagious. The first is similar to Kevin's oxygen deprivation theory: Yawning is a reflex action in response to a need for more oxygen, and it appears contagious because if one person is short on oxygen, those around him probably are, too. After all, a stuffy room is stuffy for everyone in it.
Of course, that doesn't explain why every time I even think about a yawn, I yawn. Hence, the "power of suggestion" theory. It says that a yawn, much like hunger and thirst, can be stimulated by external cues. We see or think about a yawn and get the urge the same way watching someone eat
can make us hungry.
Finally, there's the evolutionary theory. This one says a yawn is a throwback from our furrier days when we would yawn to show our teeth, and hence our prowess. Zoologists speculate many animals yawn for this purpose. So when someone near us yawns, our subconscious Neanderthal responds to the "aggressive challenge" with an
The evolutionary explanation seems shaky to me. To test it out, the next time you're bored in a board meeting, snarl at people and see if that provokes a few yawns. Somehow, I doubt it.
*end of article*