Why is yawning so addictive?

I don’t know why, but I yawned when I read this…really!

It is contagious, eh?
mwarghhhh

From eHow:

The “Sympathetic” Yawn
A widely noted phenomenon is that yawns often seem to be contagious. Seeing another person yawn can cause us to yawn even when we are not sleepy or bored. Perhaps even reading this article caused you to yawn!

Scientists believe that our yawn reflex may be a result of our evolutionary history. Yawning when others yawn has the effect of synchronizing a group of people. This sort of herd unity and synchronization would have been essential to the survival of our human ancestors in the wild.

Another theory is that the contagiousness of yawning is due to specific brain neurons, called mirror neurons, that cause us to imitate what we see. When we witness a yawn, especially when we are in the same room with a person (rather than watching them on television, for example), it triggers these neurons to fire. When these mirror neurons activate in response to seeing someone yawn, they can cause us to do the same.
The Yawn Reflex and Empathy
Studies have also found a connection between empathy and the phenomenon of yawning when others yawn. People experience more contagious yawns when they witness someone they care about yawning, as opposed to watching a stranger yawn. Similarly, if you look into the eyes or face of a person yawning, you are more likely to yawn in response.

Further studies have shown that people who are highly empathetic tend to have a stronger yawn reflex. There seems to be a strong correlation between the degree of a person’s empathy and how likely that person is to yawn when seeing another person yawn.

Read more: Why Do We Yawn When Others Yawn?

I don’t know, but thank you for not saying “addicting”. Kiss kiss!

How does that come into play with the fact that we yawn when we are oxygen deprived?

@JilltheTooth I totally yawned when I read your answer haha.