Why yawning is contagious to some creatures, i.e. human?
Some studies have proven against a common misconception that yawning has something to do with concentration of oxygen or carbon dioxide in the brain.
In fact people who need more oxygen in their brain may not yawn quite often.
The reason why we yawn is because we want to cool down the temperature of our brain by letting cooler air contact with blood vessel in our head.
An experiment shows that person with an ice bag on top of his head yawn less frequently.
This holds true for other animals.
An experiment shows that parakeet only yawn at certain range of temperature.
Unfortunately, yawning is not contagious for some animals like parakeet.
Contagious yawning in fact can be advantageous to some animals, which enhances the awareness among groups.
Further studies show that contagious yawning is linked to the sense of empathy (share the feeling).
For instance, social impaired children yawn less frequently when they see other yawning.
Yawning frequency can have different level: family> friend>people known>stranger.
Some other animals yawn for different purposes.
For example, monkey yawns to show its sharp teeth; penguin yawns to attract mates; snake yawns to make adjustment on its breathing.
December 2013
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