Why are Yawns contagous?

Question

Why are Yawns contagous?

Answer 1

Yawning is contagious. But not in the same sense as when you say that chicken pox is contagious. Chicken pox is due to a virus. Yawning is not due to an infection.

The notion that we yawn is to increase oxygen has not been proved.

Some experts think that yawning plays some role in increasing alertness.

Usually a long wait, a monotonous job cause yawning.

Researchers have shown that a yawn may force blood through cerebral blood vessels to increase alertness.

When bored one may yawn and another in a similar situation may yawn as a "reflex response".

What ever it may be, on a plane , a yawn is an excellent way to balance the air pressure between the cabin air and the middle ear during ascent or descent.