Contagious Yawning

[dodgymanc]

Why is the activity of yawning so contagious?

[MargeB]

It's seen probably as being a social signal: 'I'm bored with what you are saying and it's time to change the subject'.

Another fact (and forgive me, but I find this FASCINATING) is that susceptibility to contagious yawning varies from person to person: Some will not yawn at all if you yawn, others can't help but doing it. I lie at the upper end of the spectrum.

Now (here's the fascinating bit): take a big bunch of people (say 1000), and test them all for contagious yawning: you get a fairly even spread. Then test them for a battery of tests of 'empathy-like tests' (basically lots of things found to be deficient in autistic people: understanding faux-pas, for example). What you find is that the extent to which you are a victim of contagious yawning can be fairly well predicted from your score on the 'empathy-like' test: if you contagiously yawn more easily, you are more likely to 'get' faux-pas situations (those odd situations where it's not simple to state why you DON'T do something:you just 'don't').

Why is this? Hard to work out. One thing is for sure: when you yawn, a bunch of neurons fire off in your head, to tell your face how to do it. If I yawn AT you exactly the same neurons fire (ie you almost 'yawn' too) but the front of your brain tells the body not to carry out the action. Curiously, there seems to be a disturbance in the functioning of these 'mirror' neurons in autistic people. (I believe the paper on this is by Platek (sp), available on the web perhaps).

[MargeB]

It is on the web:

http://webperso.easyconnect.fr/baillement/contagion-platek.html

Truly fascinating.

[OBonio]

I've read that it is a pack thing (as in Lions). Yawning, they think, signals a preparation for change in pace in upcoming events (ie, going to bed, waking up). When surrounded by people, it is a signal to the rest of the pack that they too might want to go to bed, go on a hunt etc etc. Just a theory, but it does seem to explain it quite well.

[OBonio]

Oh, the book it was in is Counting Sheep. An interesting read to say the least.

[oligopoly]

I remember hearing a while ago that 'the Chinese' (i think) believe that yawning spreads from one person to the other. ie one person first yawned and this carried on from person to person and back round in a loop for infinity

[stevie21]

andy hughes, if your evidence knocks out one theory are you saying, then, that foetuses exist in the womb in packs and they have a leader who signals when it's time to be tired and when to hunt?

Do foetuses have such finely honed social skills at such a tender age?

[stevie21]

My poorly expressed point was that IFa yawning foetus is sufficient evidence to dismiss the theory that it's to get a gulp of oxygen then it'd presumably be enough to dismiss any social theory as well : e.g. sending or receiving a non-verbal signal that it's bedtime.
That'd leave us not knowing why foetuses yawn but realising that it's innate (or very very quickly learned) and that maybe the function of a yawn changes later to become a social signal (or a gulp of air).

Sorry, this deviates completely from the point of the original question and isn't even *that* interesting!

[freshdaisy]

I don't believe that you just have to see someone yawn to start yawning! Since reading this question, I haven't been able to stop! I only have to hear or read the word and I'm off... why is this?