The human race has scaled the tallest mountains, charted the deepest oceans and played a quick front nine on the freaking moon, but there's one frontier that still largely mystifies us: our own bodies.
There are everyday phenomenons you'd think must have been explained ages ago, but in reality asking these simple questions of a scientist will net you at best a shrug, and at worst some bullshit he just made up off the top of his head.
The act of yawning is baffling to experts for two reasons. One, it doesn't actually seem to serve any purpose. Seriously, when you feel a yawn coming on, suppress it. What happens? Do you go into convulsions? Is your face racked by pain? Does blood shoot from your nose? No. Not a damned thing happens.
Equally baffling, though, is the contagious nature of it. Yawn, and whoever sees you will yawn. When a chimpanzee yawns, the other chimps yawn. If you yawn, you can make a dog yawn. Seriously, try it.
Odds are you've yawned once just because you read the word "yawn" several times above. Why?
Science's Wild-Ass Guess:
Your science textbook in elementary school may have said that low oxygen levels in the blood triggered yawning, with the yawn providing a quick influx of the gas. That was the prevailing theory going back to the days of ancient Greece. As is usually the case though, it turns out people from back in the day didn't know what the hell they were talking about. In fact it's been found yawning may actually decrease oxygen intake. Makes sense, when you do hard exercise you don't start frantically yawning. You don't see athletes yawning in the middle of a sprint.
Unfortunately, the alternatives are quite a bit more insane.
Such as the theory that yawning is the body's way of controlling brain temperature. Yeah, apparently scientists think our brains function with all the complexity of an old car engine. And you know how you're always yawning when you wear a hat, right? Right?
The proof of this was experiments in which it was found people with cool packs attached to their heads yawned less. Unless there could be some other reason people sitting in an unfamiliar lab with ice packs on their heads weren't much in a yawning mood...
As for why yawning is contagious, some scientists have pointed to human being's primitive herd instincts, figuring group yawning could have helped regulate sleeping patterns so that a "whoops, we all fell asleep at once and got eaten by giant sloths" situation didn't develop.
This remains merely a theory though, and of course still doesn't explain why people yawn while on their own.
Hey teenagers, need something else to add to your angst pile? Turns out these awkward times you're going through are far from universal in the animal kingdom. It's only humans Mother Nature decided to kick in the nuts, cursing to an opposite sex-repelling bubble of greasy clumsiness.
What evolutionary sense does it make for guys to be confined to their parents' basements smearing Clearasil on their face during their prime sexual years?
Yeah, a tie, that'll do it.
Scientists can't even agree when exactly the adolescent phase evolved. Some believe teenagers were awkward balls of nerves and nose grease as early as the Homo erectus era over a million years ago, while others think it's a much more recent development. Until they find a Homo erectus skeleton holding a fossilized iPod filled with My Chemical Romance songs, we may never know for sure.
Science's Wild-Ass Guess:
Some scientists argue that guys' half-decade of dorkdom is designed to force them develop traits chicks dig, like a sense of humor, artistic talent and conversational skills. Honestly though this theory sounds like the wishful thinking of scientists who don't want to face the ugly truth that their memorization of the periodic table and every Battlestar Galactica episode won't be getting them in any girl's pants ever.
Plus, it's hard to buy from an evolutionary perspective. Are we seriously to believe that all the guys who didn't have awkward teen years somehow got bred out of the population? Where we went to high school, while the clumsy awkward teens were trying to discover our charming adult personalities, the cool teens were busy having sex with one another. After a few thousand years of that, shouldn't evolution dictate that we all turn into Sean Connery on our 13th birthday?