🥱 Why do we yawn, and is it really contagious?

Why do we yawn? Yawning is a universal gesture. Everyone yawns, from babies still in their mother's womb to the elderly. However, the exact reasons for this reflex are not well understood. Is it just because we're tired, or does this movement have a specific purpose? And why, when we see someone yawn, are we immediately tempted to do the same?

The mystery of yawning

A yawn is a deep inhalation followed by a slower exhalation, accompanied by stretching of the face and often the body. It's found in many animals, which suggests it's an ancient mechanism preserved throughout evolution.


Scientists long believed that yawning served to oxygenate the brain. But this idea isn't really confirmed: we don't yawn more when the air is low in oxygen. Another, more recent hypothesis suggests that yawning helps regulate brain temperature. By taking in a big breath of cooler air and stretching the jaw, we might promote increased circulation that slightly "cools" the head. This would explain why we often yawn during transitions, for example when moving from wakefulness to sleep.

It's also possible that yawning plays a role in alertness. Rather than making us fall asleep, it could be a way for the brain to wake up a bit, like a small reset when we're tired or distracted.

Contagious yawning

Then there's one of the most surprising aspects: yawning is contagious. Just seeing someone yawn, hearing them, or even just thinking about it - and perhaps even while reading these lines - can make you want to do it yourself. This phenomenon isn't yet fully explained, but it's thought to be related to empathy and mirror neurons, those brain cells that prompt us to imitate others to better understand them.


This contagion isn't exclusively human: it also exists in some social animals, like chimpanzees, dogs, and even lions. This suggests it's not accidental, but perhaps a tool for social cohesion. Sharing a yawn might unconsciously synchronize a state of alertness or rest within a group.

In summary, yawning isn't just a sign of fatigue. It's a complex reflex that combines physiology and psychology. And if you felt like yawning while reading this article... that's proof that contagious yawning works very well!