yawn

Yawning is incredibly contagious.

I made some of you reading this yawn simply bywriting the word "yawn ".

The people who yawned when they saw you yawn ,meanwhile were infected by the sight of you yawning - which is the second kind of contagion.

They might have even yawned if they only heard you yawn because yawning is also aurally contagious: if you play an audio tape of a yawn to a blind person, they''ll yawn too!

And finally, if you yawned as you read this, did the thought cross your mind - however unconsiously and fleetingly - that you migh be tired? I suspect that for some of you did it , which means that yawn can also be emotionally contagious.

Simply by writing the word I can plant a feeling in your mind.

Written by Malcom Gladwell in the book The Tipping Point