Why do we yawn – and why is it catching?

You are sitting in a meeting or a long class. Someone near you opens their mouth wide and yawns. A few seconds later, you yawn too. Sound familiar? You are not alone. Yawning is one of the most contagious things that humans do.

Most people think we yawn because we are tired or bored, and that is partly true. We often yawn in the evening, early in the morning and when nothing interesting is happening. But that is not the whole story. Athletes sometimes yawn just before a big race, and many people yawn when they feel nervous.

So what is the real reason? One popular theory says that yawning helps to cool the brain. When we yawn, we take in a lot of air, and this may bring the temperature of the brain down a little, so we can think more clearly. Some studies seem to support this idea, but scientists have not proved it yet.

The strangest thing about yawning is how easily we “catch” it. Seeing someone yawn, hearing a yawn or even reading about yawning can make us do it. Some researchers believe this is connected to empathy: we copy the people around us, especially people we know well. Interestingly, some dogs seem to catch yawns from their owners.

Yawning starts very early in life. Doctors can see babies yawning in scans months before they are born.

Are you yawning now? If so, don’t worry – it probably means your brain is working perfectly.