Why do we yawn when we see others yawn?

Question

Or when we read about it or talk about it or anything?

Answer 1

Yawning does perform several ways. I always did it during warming up as I began exercising and I know others do it then also so the hyperoxygenating function seemed possible. But the most recent studies relate the yawn to temperature regulation for the brain.
http://www.baillement.com/dossier/cooling-gallup.html
Their experiments showed a direct correlation between the brain's temperature and propagation of the yawn between people so they can easily suggest an adaptive function for the behavior. The socializing function would then follow the preexisting adaptive function of the yawn.

Both yawning and laughter are contagious social behaviors. They may be part of what is called 'phatic' behavior helping create social bonds in nonverbal means. If true then seeing is doing because seeing it ( a yawn or laugh) triggers the pattern recognition and releases the fixed action the yawn or the laugh. It is a shared basis of experience/communication.
We can use the yawn to deliberately signal meaning depending on where and when. However that is all based on the shared experience of reflexive yawning.

http://www.howstuffworks.com/question572.htm

Answer 2

"New research suggests rather than being a precursor to sleep, the purpose of yawning is to cool the brain so it operates more efficiently and keeps you awake.

The theory could explain a puzzling question about subconscious human behaviour - why many of us yawn when we see or hear another person doing it, or even read about it or even just think about it?

The brain cooling theory says that when we contagiously yawn we are participating in an ancient, hardwired ritual that evolved to help groups stay alert and detect danger.

"We think contagious yawning is triggered by empathic mechanisms which function to maintain group vigilance," says Dr Gordon Gallup, a leading researcher at the university. "


John H

Answer 3

This is a perennial mystery. I've never read even a satisfactory explanation of why we yawn in the first place. Given that many mammals yawn, I imagine it has some evolutionary utility. What? Not clear.

EDIT: The conjectures posted below are, unfortunately, still conjectures. And while evolutionary just-so stories are often compelling, in the end there is no evidence that these stories are correct.