Why yawning is contagious

The BBC reports on a recent study by the University of Albany in New York, examining why yawning can be contagious. The researchers suggest that the purpose of yawning is to cool the brain so it operates more efficiently and keeps the yawner awake. They cite the example of paratroopers waiting to skydive being frequent yawners (trust me, if ever in that situation, I can say with 100% certainty I would not be yawning).

The study proposes three alternative explanations for contagious yawning, which only about half the adult population is susceptible to:

* A protective mechanism to make a group more alert
* A form of herding behaviour
* A means of communicating sleeping times

Read more via the link above. The BBC report says most creatures on earth yawn, even snakes and fish. I’m not sure how a person would tell if a fish yawned. But that reminds me, for me the fish tank scene in Evan Almighty was worth the cost of the movie ticket by itself.