Why is yawning contagious?

Question

Why do we yawn when we see others doing it, or even when we read about yawning?

Answer 1

I've heard that it's an evolutionary development that occurred, in part ,because when people started co-habitating in groups or clans it was helpful for them to be on the same circadian "sleep" schedule. It helped group unity.

Answer 2

People yawn because of lack of oxygen in their brain, so when someone yawns, they are taking in extra oxygen-therefore taking some of everyone elses. This makes a lack of oxygen for others nearby-so they yawn too, to feed their own brain.
Makes sense to me!!!

Answer 3

yawning is described as a reflex action which occurs when there is lack in oxygen inside the body therefore the person needs to inhale large volume of air in order to raise the level of oxygen in the blood the lack in oxygen is a result of lack in oxygen in the atmosphere which means anyone positioned beside a person who yawned will eventually yawn too.

Answer 4

yawning is a sign of boredom. when one gets bored, the psychological impact on others is that they too should get bored. therefore, yawning may be contagious at some times

Answer 5

Well, from what I know, no one is sure, but there are a lot of hypotheses, some of which you can read up here
http://www.world-science.net/exclusives/050309_yawnfrm.htm

But there are some hilarious theories as well like...
"I once heard that when someone yawns, they change the air pressure so you have to yawn as well to fix it!"

So go figure :-)

Answer 6

It's highly suggestive...even if unconscious

Answer 7

because the human brain is a sucker for suggestion

Answer 8

( yawns ) IDK