Study suggests why yawns are contagious

These scientists didn't sleep on figuring out why you yawn when we yawn
Just getting ready to be my best self! (ID 135648694 © Dalia Kvedaraite |


Even just the sight of this emoji might trigger it.

The need to yawn.

There's just something about a yawn. When we see another person's mouth open in that familiar pose, the long, loud sigh, the squinty eyes, it takes everything in our power not to follow.

So why is that? Why are yawns so darn contagious?

A new study led by researcher Andrew Gallup from the State University of New York Polytechnic Institute has suggested a reason. We all feel the need to yawn together because we're trying to synchronize (or match up) our behaviour and alertness.

It's like a subtle alarm bell across a group of animals: Wake up! Danger could arrive at any time!

Oxygen in, brain cools down

Embed from Getty Images

"I'm yawning BECAUSE I find what you're saying is super interesting! I want to pay attention!" (Getty Embed)

This theory makes a lot of sense when you think about what a yawn actually does to our bodies.

When we yawn, we take an extra large, deep breath of oxygen. Because oxygen is so vital to our bloodstream and the functioning of our muscles and body systems, it makes sense that we would be more alert when we do this. But a yawn also introduces cooler air into our bodies, which can regulate our brain temperature.

In short, it cools a possibly overheated and/or distracted brain. It's like quickly restarting an overloaded computer. Whether we've just woken up or have been up for hours, a yawn always manages to leave us a little more refreshed and zeroed in.

Get it together

So if a yawn does that to one animal, you can imagine what it would do for an entire group. Suddenly—whether it's a group of mice, monkeys, or humans—that entire group would be more alert and aware of danger. This makes extra sense when you think about why we tend to yawn.

Because we're bored or tired.

Since danger is everywhere in nature, yawning protects a group from dropping their guard when things appear to be safe. That's pretty smart, nature!

More alert after a yawn

Embed from Getty Images

"Wake up, you two! Danger could be anywhere!" (Getty Embed)

But is this theory right, or just a guess? To test this out, Gallup did an experiment with a group of people. He showed people a selection of images—some of them were of threatening animals, others were non-threatening. Then he timed their reactions to the threatening animals both before and after the people had yawned.

Overall, people were quicker to react to the threat after they had yawned. Yawns appeared to make them more alert.

More tests would need to be done before we could accept this as fact, but it certainly changes how we're viewing a yawn. Until next time, stay alert everyone!


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  1. My sister didn’t yawn when I yawned! Maybe we weren’t facing each other? She’s a 5 almost 6 year old! I just turned 8! Is it because of age?

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