health and medicine question #381
Adam Roda, a 12 year old male from the Internet asks on May 25, 1998,Q:
Why do we yawn when we see someone else yawn? Why is it contagious?
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Jody Culham answered on May 25, 1998, A:If you found this answer useful, please consider making a small donation to science.ca.
Surprisingly little is understood about yawning. Here's what we do know:
- all animals yawn
- most yawns occur during the hour before sleeping and the hour after waking
- seeing a picture of someone yawn makes you want to yawn too
- watching a movie of a yawn is even more powerful
- no single feature of the face (e.g., mouth only) is as good as the whole face
- yawning is more contagious when people don't know they're being watched
- yawning is generally believed to help arouse the drowsy person (so they inhale more air and get more oxygen to the brain) though some believe it just helps communicate how drowsy someone feels