We are at a boring family gathering. Out of politeness we try to maintain composure and pretend that we care minimally about what our older relatives talk about.
But the little ones in the house don’t care about composure. They get bored and have no qualms about yawning as an obvious act of such a tedious meeting. The breath of invisible air travels through the room. It is approaching us, little by little. It takes shape from the depths of our interior and, without being able to avoid it, we respond to the yawn by imitating it.
While the speaker looks at us with a look of indignation, we wonder… Why is yawning contagious? Let’s find out below.
Yawning is a human and not-so-human act that, although it has aroused the interest of the scientific community since science was science, it remains quite mysterious as to why it originates, and even more so why it is contagious. However, some things are clear about such a peculiar involuntary act.
The first thing is that We manifest it very early, even before we are fully formed, in the womb You can already see how the fetus yawns after just 20 weeks from conception.
Furthermore, humans are not the only ones who yawn. It has been seen that animals very close to us also yawn, as is the case of chimpanzees and dogs, respectively. Curiously, it has also been observed in fish, birds, wolves and elephants, animals that, to a lesser or greater extent, have very clear social behavioral patterns.
Although general culture has already told us that we yawn more when we are about to go to sleep and have just woken up, scientific research has confirmed this assumption. Besides, We also yawn when we feel hungry and, of course, when we are very bored
But what is surprising about yawns is their high degree of contagion, even though they do not exist physically, they are just actions. It has happened to almost all of us that someone around us yawns and, without being able to avoid it, we start yawning with him. This is not at all strange, given that it is noted that about 60% of the population is sensitive not only to the act of seeing others yawn, but is also sensitive to hearing others do it and even reading the word “yawn.” . At this point, how many yawns have you already had?
Yawning theories
Let’s go by parts. Before understanding how yawning is spread, it is necessary to understand why it occurs in the first place
At first glance, yawning does not seem to have a good or bad effect on us. If it were something harmful, sooner or later we would have noticed some disadvantage associated with yawning and, without digging too deeply, it doesn’t seem to offer us anything advantageous.
However, taking into account that this involuntary act occurs in other species and, therefore, has survived throughout evolutionary history it has to have some use.
It is for this reason that in the scientific community, up to three theories have been proposed, with a lot of support, to explain why yawning occurs.
1. The theory of oxygenation
Already before our era, the Greek physician Hippocrates of Cos (460 BC – 370 BC) supported the idea that we yawn as a mechanism to eliminate the harmful air that we accumulate inside us In some ways, it seems he wasn’t too far off the mark.
The oxygenation theory of yawning defends the idea that when our blood oxygen levels decrease, drowsiness occurs. To counteract it, the brain makes you yawn in order to introduce a lot of air into the body, to quickly raise the levels of the gas of life.
However, although quite logical, this theory has its detractors, basically due to the existence of another mechanism that seems to be very effective for this purpose: breathing quickly, as happens when we do sports.
If oxygen levels in the blood are reduced, it would be logical to think that, rather than yawning, the body would speed up breathing, a process that implies a greater supply of oxygen to our bloodstream and that is relatively easy to control.
2. The activation theory
As we have already seen, and almost a general knowledge of culture, is the fact that It is known that yawning is more frequent before and after sleep That is, they occur when we feel very sleepy.
The idea behind activation theory is that we yawn to increase our level of alertness. That is, our brain sends us a message that we should be more on the lookout.
However, and despite the fact that there is a lot of research that suggests that this theory could be true, it is still quite doubtful that the levels of alertness before and after yawning are significantly different. It’s not that we yawn and are as alert as if we had had a cup of coffee…
3. The theory of thermoregulation
Although the other two theories have some scientific support, The theory of thermoregulation is the one that has gained the most strength This theory argues that yawning regulates the temperature of the brain, like cooling.
This makes sense, given that it has been observed that the body temperature is precisely the highest of the day and that, by yawning, we would be able to reduce it and make our brain work better.
Also It has been observed that if the ambient temperature is warm, people yawn more, while low temperatures have the opposite effect. In fact, it has been seen that putting wet cloths in very cold water on the forehead makes yawning practically disappear.
Causes of this phenomenon
Although it has been seen that yawning is present in many species, the contagion of this involuntary act is somewhat less common In addition to humans, other species such as dogs, wolves, chimpanzees, different types of fish and birds, and also elephants can catch yawning. Based on the fact that most species in which yawning is contagious also have complex social structures, it has been suggested that yawning would have a relational function.
One of the hypotheses about yawning is that it is a communication and synchronization mechanism between individuals of the same species. That is, it would serve as a way to organize collective behavior, coordinating the behavioral patterns of the group members.
This makes sense since yawning is not the only thing that is contagious In the human case and also in dogs, if you see someone eat you feel like doing it, and if you see someone move you are more likely to not sit still. Yawning would serve to put the group in synchrony, either maintaining the degree of activation or ensuring that everyone thermoregulates correctly.
2. Empathy
As surprising as it may seem, it could be that the degree of empathy is behind how contagious yawning is. In this case it would not be just a mechanism to make the rest of the group imitate it and thus synchronize, but rather a way to be able to tune in behaviorally and emotionally with others.
Using neuroimaging techniques, it has been discovered that yawning activates the same neurological mechanisms involved with empathy in addition to activating the well-known mirror neurons, cells specialized in mentally replicating the movements we see in others, allowing motor learning.
