Yawning is not always a sign of fatigue or boredom. Perhaps it is not a gasp for air, as is sometimes thought. But why do we yawn?
New insight
Recent research suggests that yawning is a way to cool the brain.
The discovery
We yawn most at a temperature of 20 degrees. At temperatures around the freezing point and around 37 degrees we yawn a lot less. This was apparent from the study, for which various parts of the world were examined when people yawned the most.
Statement
If we do indeed yawn to cool our brains, it makes perfect sense:yawning to cool the brains only makes sense if it's cooler outside than inside our body. And when it's very cold outside, the brain doesn't need to be cooled.
