Why is yawning contagious?

If you yawn while reading this title, it's no surprise. Just reading or seeing images of yawning is enough to make you want to yawn and yawn without understanding why. It's not because your brain needs oxygen.

Some theories suggest that yawning is a social clue (like laughing) to exchange information and organize behaviors in groups. By unconsciously passing from one person to another, the yawn can convey information like " I'm tired ", or " This play is so boring " through a collective round. Such a tool may have been born and has become useful since the time when humans had no language.

But does science support this explanation? A 2005 study captures the human brain when they yawned and found a special brain activity in the area related to imitation. So if the next time you're thrown an uncomfortable look at yawning during a meeting, explain that it's just a form of medieval communication.

(Photo: VNN)