Something we all do almost everyday, yawn, is often just an afterthought. We process yawns socially and interpret them as indiciating that someone is tired or bored, but according to some new research there is more to the story. First, a new theory on yawning is that a yawn helps cool the brain. Subjects in a study yawned more when their brains were warmer.

Next, most people have recognized that yawns are contagious. An evolutionary theory suggests that we are biologically predisposed to yawn when soemone else does either because we are helping each other stay alert to dangers (actualy helps us stay awake) or that it is some anxiety ‘herding ritual’. It is fascinating to me that such a basic behavior is still so mysterious. It also might make us all think twice before taking a yawn during a social interaction as some sort of insult or indication that a conversation is boring.

Will Meek PhD is a psychologist in Vancouver, Washington, and writes weekly at his blog: Vancouver Counseling.