Why is yawning contagious?

How many of you are yawning right now after just looking at this picture or reading the headline to this post?

The latest research shows that its one of three possiblities:

It is a protective mechanism to make a group more alert
Or, it’s a form of herding behaviour
Or it’s a means of communicating sleeping times

But there are other theories. It’s been suggested contagious yawning could be a result of an unconscious herding behaviour – a subtle way to communicate to those around us, similar to when flocks of birds take flight at the same time.

Another theory suggests contagious yawning might have helped early humans communicate their alertness levels and co-ordinate sleeping times.

Basically, if one decided it was time to sleep they would tell the others by yawning and they would do it in return to show they agreed.

Chimpanzees also suffer from contagious yawning, according to researchers at Kyoto University in Japan. They are thought to be the only other creatures, apart from humans, who do so.

Interesting stuff. I couldnt stop yawning just reading this article. Was that because of this primative instinct inside me or because this is a boring post? Who knows!

via BBC