A complex behavioral reflex, yawning is natural in humans, but still full of mystery for science.
Although it may elicit disapproving looks in certain situations, yawning is necessary for the body.
Doctor Jean-Marc Sène explains this mysterious reflex to us in Bonjour! La Matinale TF1.
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It is one of the most common gestures that can sometimes embarrass us: yawning. It happens unexpectedly, spreads like wildfire from person to person, and has remained a mystery for a long time for the scientific community. Jean-Marc Sène explains to us what is hidden behind yawning in “Bonjour! La Matinale” on TF1.
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What happens when we yawn?
From the Latin “badare” which means to open the mouth, yawning is a complex so-called “stereotypical” behavior. It is an involuntary contraction of the jaw during which we inhale for a very long time and exhale more quickly. This gives rise to several interpretations. When we yawn, scientists have noticed that we secrete serotonin, dopamine and acetylcholine in the brain. These neurotransmitters intervene in particular on our state of alertness. When we yawn, the neck muscles also contract. Their purpose is to open the larynx and pharynx to let air into the lungs. The diaphragm also contracts to inflate the lungs. The goal? To oxygenate the blood.
Why do we need to yawn?
This reflex increases alertness and attention. How? Scientists have several hypotheses. Yawning could be the result of a change in brain activity, we would change neural circuits, that is to say we would move from an internal reflection (like meditation) to a circuit of attention to the environment, that is to say focused on the outside. It is a kind of transition between sleep and wakefulness.
Second hypothesis: venous drainage. When yawning, we contract our muscles, we bring air into the body and when we relax, there is an effect of blood flow and venous return. When yawning, we would reduce certain substances that make us sleepy. Last hypothesis of the scientists: yawning would regulate brain temperature.
Yawning, a proof of empathy and sociality
According to a 2020 study published in the scientific journal PLOS Oneyawning is linked to empathy. The study showed that people are more likely to have a communicative yawn when they are with their loved ones. The closer the bond, the deeper the yawns! Moreover, it is not uncommon to see the most social animals yawn in reaction to their peers: primates, cats or dogs can, in fact, be caught by this behavioral reflex!
