Have you ever noticed that when a person near you yawns, you may start yawning too? This is called contagious yawning. "Contagious" means that the behavior spreads from one person to another: when one person does something, it can cause others to do the same thing.
Why Do We Yawn?
There are numerous theories about why people yawn. One of the first theories for yawning was created by Hippocrates who suggested that yawning was a way to release bad air from lungs. However, yawning seems unlikely to have a function in respiratory system.
Another idea which is more popular is that yawning brings more oxygen into the brain to wake people up. But in 2007, researchers at a university in New York came up with a new idea: yawning helps cool the brain.
Scientists found that people yawned more often in situations where their brains were warmer. The idea is that yawning cools the brain by increasing blood flow and bringing cooler air into the body. Cooler brains work better than warmer ones.
This may also help explain why yawning is contagious. People are more awake when their brains are cooler. As people evolved over time, contagious yawning helped people stay awake. This was important in times of danger. It’s very possible that the person yawning could have been signaling to others to stay awake.
There is also a common misunderstanding about yawning that people yawn because they want to sleep. This research shows that it does not true because people yawn in order to stay awake. The next time you are talking to someone and that person yawns, you can tell yourself that he or she actually wants to stay awake, not go to sleep.