Although yawning seems like a small, everyday action, recent studies have found that it causes an unexpected reaction in the ...

Seeing or hearing someone yawn can make you yawn. This phenomenon is not limited to humans; some animals experience contagious yawning, too. But why is yawning contagious? Brain cells called mirror ...

I read recently an explanation for yawning that is plainly wrong. The same idea has surfaced regularly over the years. Any idea, good or bad, is hard to kill. Yawning by this account is performed in ...

Researchers believe the yawning robot may have triggered some biological mechanism in the chimps that they associated with sleep. Image: Popular Science composite, Getty Images/ RMJM, Aline ...