Yawning is not your body asking for more oxygen. Your brain has a cooler reason.
Is it about oxygen?
For years, people blamed a lack of oxygen. But people breathing pure oxygen yawn just as much.
So what does a yawn do?
Sure, we yawn more when we are sleepy or bored. But many scientists think the yawn itself helps cool your brain. Your jaw stretches wide and speeds up blood flow to your head. And a deep breath of cool air helps cool that blood. In one test, people with a cold pack on their forehead barely yawned.
Why are yawns catchy?
Yawns also spread from person to person. Seeing someone yawn can make you yawn, too. It spreads most between family and friends.
Are you yawning yet?
And here is the funny part. Even reading about yawning can make you yawn. Did you just yawn? Now you know why.
Sources
- Frontiers for Young Minds: Why do we yawn?
- American Scientist (Robert Provine): Yawning
- University of Washington, Neuroscience for Kids: Yawning
- University at Albany
- ScienceDaily: Psychologists Attribute Yawning To The Need To Cool The Brain And Pay Attention
- The Naked Scientists: Why do we yawn?
- Britannica: Why Do We Yawn?
- The Scientist: Yawns More Contagious Among Friends
- ABC News: Yawns More Contagious Between Loved Ones
