Thread: When do we yawn

When do we yawn? I was told many things like when we are out of oxygen, when we are sleepy, but what's the truth?

From what I recall, it was believed to be due to oxygen levels for the brain. Like each "type" of yawn is linked to either having too much oxygen or too little. I think studies suggest that it is due to cooling the brain. We also have to equate the psychology behind yawning because we see others do it as well. I too would like to know the TRUE reason behind it, seeing there is one.

There's no real scientific agreement on yawning - which might be a consequence of there not being enough science about fatigue, sleepiness and the like.

I'm not so sure about the psychology side, though. Exactly the same thing happens with coughing. There's quite a lot of shame and guilt when you're the first one to cough in church or during an intense moment in a theatrical performance. From attentive silence straight into shuffling, coughing, fiddling about for tissues and cough lozenges, the mood is broken. Same thing for laughter. The only reason we don't concentrate on that is because it's usually welcome.