I read years ago that it was to do with tribal/social efficiency.
It’s getting late; pack leader yawns; others yawn & feel sleepy; whole pack finds a comfy place & goes to sleep. Benefits: no-one gets lost taking a solitary nap; the whole pack gets rested at the same time and so is wholly alert after their sleep, allowing better hunting &cetera.
Sorry, don’t have a cite.
Jinty, that would only work if the person doing the initial yawn WAS in a position to be counted as pack leader i.e. someone in authority in some way, whether actual authority (teacher etc) or implied (bigger, stronger, more respected etc). It doesn’t seem to work that way as far as I can see
I can’t go with the “yawning to supply more O[sub]2[/sub] to the brain” crowd. For this to happen 2 things are required: You need to inhale significantly more O[sub]2[/sub] than during a normal inhalation and you need to hold your breath for a longer period of time in order to give time for the O[sub]2[/sub] to be absorbed through the lungs.
In the normal course of breathing, we don’t use up all the O[sub]2[/sub] that we breathe in. I can’t find a cite for this but I’m pretty sure this is correct. At any rate, I don’t tend to hold my breathe before yawning so I don’t see how my lungs are going to take advantage of the extra O[sub]2[/sub] available to it.
I also think this would be an easily testable claim. Only one of the articles linked to seemed to think this was a cause for yawning and another specifically said this is not the case.
Well, hello, that’s just about my point. If it’s been studied, yet not understood, then I am left to deal with conjecture based on isolated incidents and the anecdotes we get as a result from probing the mystery further.
So, like most folks who want to figure something out, I am left to be critical of anecdotes and isolated incidents others put forward.
Okay? We are back to theories now…or just educated guesses about what causes yawning to be “contagious” - which by it’s very description of being “contagious” will lead some folks to create hypotheses with some bias, in that we must explain the contagiousness of yawning, rather than approach it from a different angle that does not get biased by worrying about it being contagious.
I was just thinking about this the other day, and thought- what a great topic for Straight Dope!
Anyway, I am of the school that the yawn is a mechanism that, amongst many other uses, is a way to get more oxygen to the brain. The “contagious” factor is the reaction of those around you to also get more oxygen, since it could theoretically be in an oxygen deprived environment.
Of course, this is all bery suspect.
It’s a long time (c. 10 years) since I heard/read this theory. It may well be BS, I can’t say for sure. Seemed a credible explanation to me at the time. The example which I remember being cited was lions (who seem to yawn a lot, at least in the wildlife documentaries I watch :D).
I don’t think it works that way in human society nowadays, because (a) we aren’t hunter-gatherers any more and (b) language (“go to sleep!”) has made such non-verbal signals unnecessary.
Where’s an anthropologist when you need one?
I thought it was a subconcious thing because the body needs more oxygen, and your (usually) tired when you do it therefore breathing shallowly. As to why others yawn when you do, I thought it was because their subconcious sees you do it and says “what the hell a little air can’t hurt”. And you can make someone yawn by pretending to yawn. I’ve done it to a horse and made it yawn about 8 times in a row.
By the way, ever see a horse yawn? It’s fuckin hilarious.
Only half your breath can be absorbed beacuse O2 is absorbed by osmosis (not right term but whatever) so levels on each side of absorption must be equal.
OK, I got snippy. I apologize. I deserve this, I think. What exactly does it mean?
I got an email once that explained that yawning caused a change in air pressure inside a room. When you yawn, others have to yawn to balance it out. I’m surprised this one hasn’t circled around as much as the “why do we park on driveways and park on driveways” pool of standard issue emails.