I was recently trying to find a list of instinctive human behaviour (i.e. based on experiment and not some blogger). The only one that I could find with much authoritative writing was yawning, but I was surprised to find that no one knew why we yawned. So, I was intrigued to read this in today’s Scotsman:
THE glazed eyes and the futile attempt to suppress a yawn as someone rambles on has long been seen as a response to boredom or as a sign the body is in need of a rest.But now scientists have thrown another factor into the mix by revealing yesterday that yawning can be a way of regulating brain temperature and preventing overheating.
The research, led by Andrew Gallup from Princeton University, is the first involving humans showing yawning frequency varies with the seasons and that people are less likely to yawn when the heat outdoors is greater than body temperature. (Scotsman)
The explanation seems pretty plausible. Yawning both increases air flow and can change the blood flow (I can actually hear it if -when – I yawn). I’m also far more likely to yawn in a warm room, when sitting still and paradoxically, it’s not the boring meetings, but the most stimulating ones that seem to trigger the most yawning.
Could it be that the brain activity of an active meeting is literally causing the brain to overheat, whilst at the same time the rest of the body is so passive that the heart has no reason to pump blood. We can almost see the evolutionary engineer in action:
“sorry love, the brain’s overheating … it’s too big for the heating system … your not supposed to have a massive brain like that and the evolutionary designer never even thought to link the brain into the heat control circuit. All I can do is add a bypass: whenever it gets too hot, that big flap will just open up letting in a draft of air to help cool it, I’ll also relay the pipe with the coolant through the hinge so that when the flap opens you get a rush of coolant through and … well it might work. But it’ll cost you ……. phew! that’s going to hurt …… 1million years of women’s in total agony as they give birth to children with heads so big. I told them it would have been much better to deliver the baby out the belly button …. but would they listen? It’s women’s own fault. If you want witty men, you’ve got to have the big brains, but then you complain that they start overheating and you think somehow a big brain’s going to get out that puny hole between your legs … it’s just not a good design, … totally botched.
If nothing else, at least it gives us an excuse next time we yawn at a meeting: “no, NO! I’m not bored, it’s that I’m finding it so stimulating that my brain is overheating”.
You can avoid yawning by taking a couple of slow deep breaths. I’ve used this technique in many a meeting or long conversation to great avail.
When I yawn it turns off my hearing to anything outside my head. I can’t hear anything anyone is saying when I yawn. But I don’t think it’s just about shutting down what I’m hearing, it’s also an effective signal to anyone in eyeshot that what we’re about is no longer really very interesting. Then again, it is also the body’s way of telling the brain that Mother Nature thinks it’s time for a nap and some REM and we better wash our face, brush our teeth, get out of these hot dirty clothes, put on some jammies, and crawl into a nice sack and get on with some more important nocternal reinvigoration. I’m sure yawning is a primal physical response to many forms of denial and that Type A personalities make/have the biggest, loudest, and longest yawns.
Of course it may be that it has nothing to do with any of these things; that they are just a coincidence of having too much turkey and dressing (or whatnot) between our teeth.
Having expanded the theory that yawning was a response to of our large brain overheating, my son pointed out that chickens yawn … and as I’m even now trying to teach them to perch (long story) I can tell you that chicken’s are the most stupid creatures.
I’m sure that humans (at the top of the Brain Chain) must have, simply had to, when they began to “communicate”, incorporate different type of yawns into everyday speech. Speech may actually be nothing more than evolved yawning. The way the world is today, with so many PhDs, I just know that someone has made the connection between yawning and primitive speech. Maybe we did get it from chickens. Turkeys are nothing but a kind of chicken, really a Dinosaur, I’ll bet there is a connection. Think of it! The first word was a yawn.