Here’s Why Yawning Is Contagious

Just one person doing it sets everyone off. But why is yawning contagious? Turns out, humans aren't the only animals with a case of the big yawns.

The big yawn

Teachers might have told you off for doing it, and your parents used it to try to get you to go to bed earlier. It’s rude to do it in a meeting, and seeing someone else doing it (even if they cover their mouth) can set you off too. Yes, we’re talking about yawning, which is pretty much only cute when your pet does it. But what is the point of it, and why is yawning contagious? There are various theories, including that a yawn is just a deep breath that helps you bring in more oxygen. Although there are many explanations of little things you’ve always wondered about, the truth is that there is no scientific consensus on why we yawn.

Why do humans yawn?

Yawning is a primitive reflex. Most animals yawn, and humans are no exception. Birds, reptiles, mammals, and even some sharks can yawn, and they’re probably asking “why is yawning contagious?” too. Although it’s associated with feeling sleepy, yawning doesn’t only happen when we feel tired. Scientists think that the reason we animals yawn has a lot to do with our brain temperature. Because most members of the animal kingdom share a similar brainstem, humans are as likely to yawn as Komodo dragons, yellow-rumped warblers, or a herd of moose.

Previous studies on humans have shown that yawning happens less during the winter, when temperatures are cooler. A nice long yawn brings in air, which your body can use to cool or stabilize your brain temperature. Scientists have observed that people tend to yawn when they’re tired or bored, and they think that it’s because their brains are slowing down due to fatigue or lack of stimulation. When your brain stops firing, its temperature drops. Animals with bigger brains tend to yawn for longer periods of time, perhaps taking in more air to cool a bigger brain. Yawning also compresses the muscles of the face and drives oxygen-rich blood up to the brain. When your cat or dog yawns, they’ll often do a big stretch at the same time. Yawning alone stretches some of your facial muscles, and adding a big stretch of your own wakes your body and brain up through movement and compression of your tissues and muscles. Equally as perplexing as yawning is sneezing—what really happens when you sneeze?

Why is yawning contagious?

It’s a scientifically proven fact that yawning is contagious, and there are several reasons why. The first is simply tiredness. If you’re not getting enough sleep on the regular, and you can’t stop yourself from yawning at regular intervals, it might be time to check out a guide to deeper sleep. The second has to do with mirrored behavior. Seeing someone else yawn in a boring lecture triggers you to yawn as well because you’re in the same environment, exposed to the same temperature and stimuli (or lack thereof). As social animals, we are inclined to mimic others’ actions if we think they will also benefit us, or to create social bonds. There are other behaviors that fall into this category too, like laughing or scratching. It all comes from our ancient brainstem! Another study even showed that students with more empathy were more likely to yawn after seeing another person yawn, although that doesn’t necessarily mean that you’re non-empathetic if you don’t catch a yawn too easily. Yawning is contagious, but you could just be well-rested!

Still, if you’re stuck in a yawn fest and you can’t seem to stop, try breathing deeply through your nose for a few minutes. That should wake you up and help you stop cracking that jaw. If you’re stuck at work for a few more hours, try a little motivation, such as finding out why money is green.

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