Surely you've ever yawned in front of another person, this one saw you do it and a few moments later, that person also ended up yawning. Therefore, surely at least once in your life you have asked yourself: why is yawning contagious? Well, seeing someone yawning, hearing a yawn, or even reading about yawns can make you yawn.
For many years, various theories have tried to explain why yawning occurs. However, for now there is no conclusive evidence.
Why is yawning contagious? Almost two-thirds of people are sensitive to yawning. That is, they will instinctively repeat this behavior if they see that someone is doing it.
The fact is that, among the most common behaviors in humans, yawning is perhaps the least understood. Thus, the explanation of why we yawn has yet to be demonstrated. Although, in any case, this behavior is usually common in other animals such as cats, dogs, apes, etc.
Theories as to why yawns exist
If this behavior exists it must be because it has some use. Now what can it be? For many years, various theories have tried to explain it. Let's see some of the most accepted.
Oxygenation theory
His most distal antecedent seems to lie in Hippocrates, who argued that yawning removed used air and renewed it for clean, fresh air. This hypothesis seems to correspond to the fact that, when oxygen levels decrease due to drowsiness, yawning would be a quick way to inject oxygen into the body.
In any case, it is a controversial theory that, as the researchers point out, has not yet been tested. Therefore, the idea cannot be confirmed or discarded in its entirety.
Activation theory
If we are aware, we yawn when the level of alertness decreases due to drowsiness, boredom, etc. Yawning would redirect attention and give us a necessary extra trigger. However, although it seems logical, the idea could not be 100% empirically demonstrated.
It is not that this theory should be discarded, it is that more research is still needed to causally link the level of activation with yawning.
Body temperature theory
This is the theory that has gained more strength in recent years, since it is the one that provides the most convincing data. According to a study by Gallup, A. C., & Eldakar, O. T. (2013) yawning would help lower the temperature to cool the brain and make it work better.
The data clearly indicates that, before yawning, there is a temperature rise that drops rapidly after each yawn. If you want to eliminate yawns, nothing like putting a cloth with very cold water on the forehead, because it has a similar effect.
In addition, these data have been successfully replicated in other studies, thus giving the theory considerable validity. However, the main investigator of the study suggests that the 3 previous theories are compatible with each other and that, although this theory has greater validity, the possibility of a relationship between the three should not be ruled out.
Why is yawning contagious?
As we said before, most people easily catch other people's yawns, just like other superior animals. There are two theories that explain it; We detail them below:
Yawning helps to synchronize group behaviors. It is part of the imitation behaviors. For example, social animals tend to carry out specific behaviors at the same time. For example, eating, moving, body posture, etc.
The second theory refers to empathy. Thus, seeing someone yawn would activate empathy brain circuits, including mirror neurons, which act as an internal reflection of the movements we observe from others.
On the other hand, it has been pointed out that some research on yawning has yielded results that have determined that contagious yawning is a sign of empathy, a peculiar form of social bonding. It also highlights that children begin to develop this contagious behavior from the age of four and that in children with autism there is half the chance that yawning will spread. Something really surprising, isn't it?