Why do we yawn and what is the function of yawns?

It may sound silly and even humorous, however the bullet phenomenon is one of the most deeply rooted in our biology. Basically everyone yawns no matter what culture they belong to.

Moreover, it is not only present in babies and even in three-month-old fetuses, but also manifests in virtually all vertebrate animals, from parrots to sharks.

But … what is it that makes yawning so ubiquitous in much of the animal kingdom? Why is yawning and why is yawning contagious? Are they for something? Below, we’ll cover these issues and many more. But first, let’s start with the basics.

    What is a yawn?

    A yawn is the involuntary action of holding the jaws open, inhaling deeply for a few seconds, and closing the jaws while exhaling briefly.

    yawning they are closely linked to the sleep-wake cycle which regulates the hormone called melatonin, which is why it was believed for many years to be a physiological phenomenon related to the level of brain activity and the response to stressful situations that can sometimes take you off guard. or because we are sleepy.

    In short, yawning is something closely related to our evolutionary origins and that it has entered the most basic functioning of our nervous system. However, knowing this does not tell us anything concrete about its usefulness. If we want to know what this curious biological mechanism might answer, we must do concrete research to find out.

    Why is it?

    If we start from the idea of ​​yawning it essentially captures a lot of air through deep breathingWe will easily come to the conclusion that yawning serves to oxygenate.

    However, this hypothesis has been refuted since the 1980s, when University of Maryland researcher Robert Proven observed that the frequency of yawning was the same whether one was in a very well ventilated room or with a lot of CO2.

    At the moment, it’s unclear what yawns are for, but a number of theories are being discussed.

    1. Exercise the facial muscles

    One of the hypotheses that could explain the function of dance is the possibility of keeping in shape and tone small muscle groups in the face that depending on our mood or the social contexts we find ourselves in, they can stay almost completely relaxed for too long.

    So when we are bored or sleepy and adopt a neutral, expressionless face, yawning can be a wave of activity that helps that part of the body regain muscle tone. It would be like an automatic way to despair.

    2. Prepare for the state of alertness and focus

    Keeping your facial muscles active shouldn’t be right for you keep them ready for action. It can also have a psychological effect: noticing this sensation could help us lighten up, making the brain more active and able to pay more attention to important things. It’s, say, a loop effect: the nervous system moves certain muscles so that this muscle activity keeps us more awake.

    3. Correct the position of the bones

    Another explanation for why we yawn would be that this action allows you to “reset” the position of the jaws, Making them better suited than before. Likewise, the same movement can help clear the ears by correcting the air pressure differences between the inner and outer ear.

    4. It has no function

    Another possibility is that yawning is of no use, at least in our species. It is perfectly possible that in our ancestors if they had served something but that by way of evolution this adaptive advantage had been lost, or that since its appearance in the most elementary forms of vertebrates, it was something totally useless.

    After all, a biological characteristic does not need to take advantages to exist. Evolution not only causes the most adaptive traits to appear and survive, but there are others that do everything and do not benefit the species that carries them. The pseudo-penis of female spotted hyena is one example.

      Why are yawns contagious?

      Another big unknown is why we are so prone to being hit by the yawns of others. In fact, we have seen that it is not even necessary to see others yawn; thinking of a yawn or seeing a photograph in which this action appears greatly increases the chances that it is entrusted to us.

      It is currently believed that at the origin of this curious phenomenon are the mirror neurons, Which are responsible for initiating “mental tests” on what it would be like to experience in our own skin what we observe in real or imagined people or animals.

      Mirror neurons can be the neurobiological basis of empathy, but one of their side effects could be yawning.

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