Yawning may cool the brain

I sometimes get asked why we yawn and I am not sure. I was taught that it was to increase oxygen supply to the blood, but research has not demonstrated that definitively. This study showed that yawning may be a way that the brain gets cooled. Specifically researchers studied contagious yawning - that type of yawning which occurs when you see another person yawn. This is in contrast to spontaneous yawning. The results showed that contagious yawning was more common at warm temperatures. However, it was not more common at very hot temperatures, such as in Arizona in the summer.