When you see someone else yawn, you don't think to yourself, 'Well, I'll yawn, too,' says Provine. 'It just happens -- it's instinctive, and it's a very primal aspect of human behavior that goes back to ancient herd mentality.'It even works if you hear someone yawn on the radio.
Monday, October 13, 2003
Yawns are contagious.
