A man is yawning in front of his computer
Scientists are still scratching their heads as to what the real reason behind why we yawn is.
Photo Credit: shironosov / iStockPhoto.com

Science-Backed Reasons Why We Yawn

We’ve all experienced it; a sudden urge rising from the deepest parts of our body that in a matter of seconds consumes us. There’s no stopping it once it starts — we have no control once our body decides to let out a yawn.

How on Earth Can I Stop Myself From Yawning?

If there is an art to it, I need to learn it. Before we can even hope to control our yawns, it’s important to understand why they happen and why they are so contagious. Is it only because we are overwhelmed with boredom or monotony? Or is there some scientific reasoning behind the phenomenon?

Although our intentions are not to bore you, we know that while reading this article, it’s likely you’ll yawn at least once or twice. This is because yawning is a condition — not a habit — that offsets a contagious chain of yawning events even when you are just reading or talking about it.


So what causes this mysterious epidemic? Before we delve into that, let’s take a look at how yawning is medically defined.

Yawning is termed as an involuntary action that causes our mouth to open wide and breathe deeply. It’s involuntary because we have been doing it long before we stepped into this world.

Robert Provine, a developmental neuroscientist at the University of Maryland, Baltimore County, says that even an 11-week old fetus yawns.

So what really happens when you yawn? Your mouth opens and your jaw drops, your abdominal muscles flex, and your diaphragm pushes down. The air you inhale fills your lungs, and after the whole movement, some of it is exhaled out.

Overall, it’s a very flattering experience for us as we frantically attempt to cover our mouths before people are forced to look at our tonsils.

Support From Scientific Theories

A common misconception is that yawning mostly occurs because we suffer from boredom or fatigue — this may or may not be entirely true.

Scientists are still scratching their heads as to what the real reason behind the condition is. They believe there is more to the actual reasoning than most people think. However, certain theories have been put out suggesting an abstract of the causes of yawning:

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Boredom Theory

Although quite genuine, this theory failed to explain why athletes or animals felt the urge to yawn before competing or attacking their prey. It would be considered pretty awkward if it is due to boredom.

 Evolution Theory

While some may suggest yawning was a primitive form of communication, this theory puts forth some similar conclusions. Proponents of this theory claim yawning began with our ancestors. They used it for intimidating others by showing off their teeth as per the findings of the theory. A derivative of this theory also suggests that it was a signal for changing activities — meaning taking over of a new habit or behavior since you found what you were doing tedious.

Physiological Theory

This one suggests that our bodies encourage yawning to draw in more oxygen. This theory can only explain the reason why we yawn in groups. Because in larger groups, there is more exhaling or carbon dioxide, our bodies try to get rid of excess carbon dioxide by drawing in more oxygen via yawning.

But if this theory was accurate, wouldn’t we all be yawning during a rigorous workout session?

Brain-cooling Theory

A recent interpretation proposed by researchers is that yawning is a way of cooling our brains. A study was conducted under warm conditions where the subjects were asked to breathe through their noses or place hot or cold packs to their foreheads. The theory says it cools down the brain making it clearer to think and be alert.

Yawning Is Contagious

According to Provine, nearly 50 percent of people who are exposed to a yawn will yawn in response. It is so contagious that everything associated with it will trigger it. An early hypothesis suggested that yawning was a form of primitive communication that was used as a medium for transmitting information.

Recent findings suggest contagious yawning can be associated with one’s capacity to feel empathy.

In order to prove that, a study was conducted between two groups of autistic and non-autistic children who were shown videos of people yawning. Although both groups yawned nearly the same amount while watching the videos, the non-autistic kids yawned much more frequently than autistic children.

Now, we all know that autism is a disorder that affects a person’s ability to socialize, including their ability to empathize. So the reason why autistic children didn’t yawn as frequently was because they are less empathetic. Also, the study suggested that kids with strong autism disorders were less likely to yawn. But that is still not certain or an absolute reason to conclude the real reason behind yawning.


We don’t know what really causes yawning or why it triggers a never-ending chain reaction even when you only hear or read about it.

For a little fun, try this experiment the next time you are in a meeting: take a big yawn and count how many people follow suit. There is a pretty good chance you have initiated a yawn outburst of deep breaths and open mouths spreading fast among the masses.