Why do People Yawn?

[epepke]

Cats yawn all the time. And they usually reveal a pretty awesome set of gnashers when they do.

My dalmatian Tess yawns quite a lot. When she does, it looks like she could swallow an entire Republican, whole.

 

[Camillus]

I'm not sure if this is off-topic, but modern respirators, of the kind they hook you up to in the hospital when you are in a coma or something, have a yawn/sigh circuit built into them. This is because it was discovered that if you force regular breathing into people, they die a lot faster.

Not quite true. Modern positive pressure ventilators don't have a "sigh" facility, but you're right that there was a time when machines did have. The theory was that as human beings normally sigh there must be a physiological reason for it and it would be a good idea to copy it. As a result you could set your machine to deliver a breath of twice the size of the other breaths it was delivering once every 50 or so breaths.

Sigh was never very popular and as we've found out more about the physiology of critical illness all the evidence suggests that the nay sayers were right and it did more harm than good.

Cheers

 

[Yahweh]

Scientific prediction: Most everyone who has read this thread or responded to it has yawned at least one time.

Scratch that, I should have said PSYCHIC PREDICTION...

Plindboe: I have yawned 5 times while writing this response.

LuxFerum: I cant read this thread. I can't stop yawning

Krazy Miller: *YAWN*

 

[Drooper]

This might be a myth ripe for debunking, but I read somwhere once that it was an inate response linked to evolutionary biological factors.

Some of the hypotheses include:

Yawning is a group cohesive activity (thos ethat yawn together sleep together sort of thing I suppose).

Yawning is a costly signal. That means, it takes excessive energy to do and hence tells others that you are fit and not vulnerable. (other examples include a peacock's display).

Yawning helps in the transition from one physical state to another (e.g. from active to inactive or vice versa).


However, I think that there is no widespread agreement.