"He and colleagues Michael Miller and Anne Clark analyzed yawning in parakeets as representative vertebrates because the birds have relatively large brains, live wild in Australia, which is subject to frequent temperature swings, and, most importantly, do not engage in contagious yawning, as humans and some other animals do."
The scientists described in this article took some pains to ensure they were studying spontaneous yawning instead of contagious yawning:
He and colleagues Michael Miller and Anne Clark analyzed yawning in parakeets as representative vertebrates because the birds have relatively large brains, live wild in Australia, which is subject to frequent temperature swings, and, most importantly, do not engage in contagious yawning, as humans and some other animals do.
Well, yawning equalizes air pressure in your inner ear (let's say decreasing the pressure). If I decrease the pressure inside my head, Boyle's Law dictates that must increases the pressure outside of my head (ie, the entire earth's atmosphere).
Which means everybody around me now needs to equalize the air pressure in their head. So they yawn.
It's been suggested contagious yawning could be a result of an unconscious herding behaviour - a subtle way to communicate to those around us, similar to when flocks of birds take flight at the same time.
"Because, statistically speaking, if conditions have induced a yawn in one person (according to these reasons), anybody else in the immediate area is likely to have the same conditions too."
Quoted because I'm just proposing it, not claiming it is true.
Misfire. Evolutionary adaptions aren't perfect. It could be that thinking about yawning in a certain way fires off the same response as viewing others around us yawn.
Interesting theory, but I want them to comment on exercise. I don't yawn much when I work out - sometimes, but rarely. This could be explained by the fact that usually when I get the hottest, I'm in a hot environment. But that's not awlays the case.
From page 2:
"Prior studies reveal yawning leads to a heightened state of arousal, so a morning yawn may function somewhat like a cup of coffee in providing a jolt of energy."
The explanation I heard many many years ago still seems right: yawning gets you more oxygen.
And if you need to test that, next time you feel the urge (meeting?), just breath deeply and it will go away.