The Perfect Yawn: “Provine, who has spent 20 years studying laughter and is the author of a well-respected book about why we laugh, is an expert on contagious behaviors. He decided (since he has tenure, and why not?) to try to design a yawn so powerful that it would make everyone who saw it yawn back. That was his goal: the 100 percent contagious yawn.” — Robert Krulwich (NPR)via rebecca