Science. Why are yawns contagious? Maybe we finally have the answer

Did you yawn when you saw the picture or read the title of this article? Even better, does anyone near you have the gap too? The phenomenon of contagious yawning is well known, but so far it is not known what it is caused by or what it is used for. A study conducted by a researcher from New York University and published in the latest issue of the journal Animal behavior may have the answer.

The scientific article proposes hypotheses to explain spontaneous yawning, and those that follow by mimicry. And some ideas we have on the subject are completely false.

The yawn is not for taking a deep breath of fresh air.

It’s a received idea! Although we take a deep breath when we yawn, this gesture does not affect the amount of oxygen in our blood. Researcher Andrew Gallup, author of the study, cites an experiment that demonstrated this by measuring the level of oxygen in the blood of humans. “It was concluded that yawning and breathing are governed by different mechanisms, and there is now agreement in the scientific literature that breathing does not have a mandatory role in yawning,” he writes.

Moreover, he reminds us that sea creatures also yawn. They open their jaws even though they are underwater and have gills.

2. Yawning does not always mean being tired.

Most of the time, they occur during a state change, either on awakening, shortly before falling asleep, or when going from concentration to relaxation or vice versa. But yawning is not always the same as falling asleep. The study also cites incidents in stressful situations: “In humans, we observed more yawning just before stressful or anxious events, for example in soldiers before their first parachute jump, in musicians before they had to play, and in Olympic athletes before a competition. This is due to the fact , that a sudden stress causes a change in our concentration, comparable to what we feel when we wake up.

3. We yawn to refresh our brains

Whether it’s because you fall asleep, or because you need to concentrate, the yawn is a reaction to giving yourself a boost or forcing yourself to pay more attention. Specifically, the study suggests that opening our mouths wide serves to cool our brains after a rise in its temperature. “The yawn is thought to be a compensatory mechanism for cooling the brain by accelerating blood circulation, ventilating the respiratory system and bringing in fresh air. And this drop in temperature has the effect of making us more alert and lively.

4. It is a form of communication in animals

If we yawn to keep ourselves alert by refreshing our brains, it seems incoherent to do so by simple facial expressions. The study explains that it is then a social phenomenon and no longer a physical one. Various hypotheses have been formulated about the cause, empathy, and usefulness of this reflex, without giving a satisfactory answer so far.

Andrew Gallup therefore suggests that chain gaps serve to transmit the information in a group of animals that one of them is a little less attentive. All the others around are therefore warned that they must double their concentration in order to anticipate the dangers. “Seeing the others make this gesture would increase the vigilance of the witnesses to compensate for the drowsiness and loss of attention of the yawner.”

In fact, it has turned out that we are more alert and attentive immediately after seeing or hearing someone yawn. An experiment was conducted in which participants had to quickly find the image of a snake in the middle of several images of frogs. When people had seen someone yawn just before, they more quickly found the threatening animal among the harmless animals.

Finally, perhaps the most important question on the subject: did Andrew Gallup, the author of the study, spend his time yawning during his research? He answered the question in an interview on the Science.org page: in the first place, yes! But over time, he got used to seeing the pictures and lost that reflex. And you, how many times did you yawn while reading this article?

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