Crocodiles yawn to keep cool, and other amazing facts
Despite being about as familiar and as commonplace as you can get, we still don’t have a clear understanding of why humans yawn.
We know we start yawning early. We know we yawn when we’re tired. We know we yawn when we’re bored. And we know that yawning can sometimes be contagious. But the function, the why, has been elusive.
A new paper by Giganti and Zilli ties together a couple of yawning’s features: that the amount people yawn varies throughout the day, and that yawns can be contagious. But does the contagiousness of yawns vary throughout the day? (…)
They tested their subjects several times on a single day. (…) Yawns are most contagious at 7:30 pm. (…)
The paper suggests there are at least two kinds of yawns, a spontaneous yawn and a yawn in a social setting. Maybe the reason yawns have thwarted our efforts to understand them is that a single explanation for yawns you make alone completely fail when you try to apply it to yawns you make around other people.
