The Science Behind Why Yawning Is 'Contagious'

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The Science Behind Why Yawning Is ‘Contagious’

By Trista - September 14, 2019

11. Human Yawns Are Contagious To Dogs

Dogs are man’s best friend for a reason. They are highly empathetic, responding almost instinctively to their owners. They may be able to detect when their owners are having a bad day and then respond by showing extra affection. Dogs are amazing.

Perhaps this high level of empathy explains why dogs can catch a yawn from humans. As with humans, their empathetic response kicks in when they hear or see somebody else – maybe another dog or even a human, such as their owner – yawn. They yawn in response.

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12. Dogs Yawn More If Their Owners Yawn

Dogs don’t just yawn contagiously. As with humans, dogs are more likely to catch a yawn from those that they are close to – especially their owners – than from a stranger. They detect the familiar sound of their owners and sometimes yawn in response.

This idea doesn’t just show how close humans are to the animal kingdom. It also shows that the empathy explanation for yawning may have some legitimate scientific basis. It is rooted heavily in behavior science, but that behavior is likely grounded in neural networks, such as mirror neurons.

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13. Yawning Helps Cool Down The Brain

In one study, a group of biology undergraduate students became test subjects in an experiment to better understand yawns. The students either cooled down their brains or heated them up by applying to their necks and foreheads either cold or hot cloths.

They then watched videos of people yawning so that they would catch a yawn in response. Those who had cooled their brains yawned less than those who had warmed them. The scientists who performed the experiment believe that the explanation is that yawning actually cools the brain down.

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14. Yawns Are Like Soap For The Blood

Keep in mind that yawns are big breaths that you take instinctively. While your brain may be responding to social and neurological cues, there are often less profound reasons for why we yawn. One is that we just need more oxygen and need to expel more carbon dioxide.

Oxygen helps cleanse the blood by removing impurities. Taking in a great big yawn supercharges this cleansing process by infusing the blood with an influx of oxygen. This means that while your mouth is open in a yawn, it basically acts as a giant filter.

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15. Yawning May Be Connected To Our Biological Clocks

Our biological clocks are internal mechanisms that regulate our activities in keeping with our physical needs. For example, our biological clocks tell us when we need to go to sleep, often at the same time each day.

Some scientists believe that yawning may be an evolutionary trait that is connected to our biological clocks. It may be an impulsive behavior in which our ancestors’ bodies signaled that they need to switch to a different activity. The act of yawning rebooted their brains so that they could effectively end one task and begin a new one.

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16. Yawning May Have Other Evolutionary Qualities

Some scientists believe that yawning may have had a different evolutionary function. When you yawn, you usually open your mouth really wide. While you may not intentionally show everyone your teeth, if you make a considerable yawn, the people around you will probably see your pearly whites.

Some believe that yawning is an evolutionary behavior that allowed our ancestors to bare their teeth to animal predators or other people who may have posed a threat. This action is part of something called “comyawn” theory. It may have some validity, alongside other explanations for why we yawn.

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17. Yawning Releases Dopamine

Dopamine is the hormone in your brain that helps you to feel relaxed. It is a neurotransmitter that helps control how you move, how you feel, and how well you remember things. Yawning actually stimulates your brain to release dopamine, which helps explain why yawns make you feel good.

This is one good reason to encourage you to try not to stop a yawn. Dopamine is essential for your overall health, and low levels of dopamine are associated with things from depression to bipolar disorder to ADHD, even schizophrenia! Dopamine is one of the pleasure hormones that make different activities feel good.

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18. Yawning Involves More Than Opening Your Mouth

When you yawn, your entire body yawns through a physiological response. Especially when you are in a great big, satisfying yawn, you may throw your head back, stretch out your arms, and suck in your stomach as you take in a large amount of oxygen — even the muscles around your skull contract.

This whole-body response helps yawns cool your brain down, one of the purposes of yawning. It may also help elicit the responses from other people – aka contagious yawning – that are part of our social make-up.

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19. Some Scientists Believe Yawning Is A Form Of Communication

Scientists aren’t sure what exactly it is that people are communicating by yawning. However, people who are more prone to contagious yawning are also more empathetic and tend to have stronger social networks than people who are less likely to yawn contagiously. Yawning seems to have a social component.

There seem to be some social benefits to yawning, particularly when we yawn in response to somebody else’s yawn. Yawning appears to be an incredibly social behavior, in addition to its physiological aspects and benefits.

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20. If You Don’t Yawn, You May Be A Psychopath

Seeing as yawning is a form of social behavior, primitive though it may be, it is actually able to indicate if someone is a psychopath. You may be irritated by a coworker; if you want to find out if there is something more to that person’s behavior, the best indicator might be that person’s yawns.

People who yawn contagiously have stronger social networks and higher levels of empathy. People who do not yawn contagiously may lack understanding, indicating that they are prone to psychopathy and psychopathic behaviors. If that coworker does not yawn in response to other people’s yawns, then there really may be something wrong with the person’s social development.

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21. Yawning Can Damage Your Lungs

Yawning is a very beneficial behavior. It has social benefits, as well as physiological ones. However, if you yawn too widely, you can hurt yourself, as one unfortunate individual found when he tore a hole in his lung.

The man was a Mr. Ou from the Wuhan province of China, who experienced a sharp pain in his chest when he yawned and stretched one morning. Doctors at the hospital found he had something called spontaneous pneumothorax, a condition that develops when a pocket of air becomes trapped inside the chest.

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22. People Have Died From Yawning

Death by yawning is an incredibly rare occurrence, and you are not very likely to experience it. However, in 2007, a 34-year-old man did perish after yawning such a profoundly large yawn that he dislocated his jaw. Lockjaw, a condition in which the jaw becomes frozen, is incredibly rare as a result of yawning.

However, in the case of this unfortunate man, his lockjaw was so severe that he was unable to breathe. He collapsed a few minutes later and had to be resuscitated by paramedics. He survived the incident but could have been much less fortunate.

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23. Yawning Can Indicate Stress

Remember that yawning stimulates the brain to release dopamine, one of the “feel-good” hormones that help you feel pleasure. It is also a social behavior that allows you to communicate something through non-conscious means. So we shouldn’t be surprised that people who are stressed yawn more.

Perhaps their subconscious brains are trying to communicate to the people around them that there is something wrong to elicit an empathetic response. What is remarkable is that this stress aspect of yawning is not limited to humans. Dogs also may yawn as a means of indicating that they are stressed.

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24. Acetaminophen Can Reduce Your Yawning

Acetaminophen is the active ingredient in many painkillers, like Tylenol and Ibuprofen. If you are experiencing a headache and are thinking about popping one of these over-the-counter medications, you may want to think twice.

Acetaminophen affects the empathetic parts of your brain, meaning that you may be less social immediately after taking something with this ingredient. Prolonged use may decrease your overall empathetic abilities. In the short-term, you will yawn less. The social and physiological benefits of yawning, which can help alleviate a headache, will not be yours.

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25. Women Yawn More Than Men

There are plenty of tropes and stereotypes regarding the differences between men and women, but this one might have some validity. In 2016, an article in the periodical Royal Society Open Science by a team of Italian scientists indicated that in an empirical study of 92 different groups, women yawned much more than men.

The scientists attributed this increased yawning to women being more empathetic than men. This notion is because women yawned contagiously – a behavior associated with social behavior – 55% of the time, while men did so only 40% of the time.

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26. Yawning Can Distort Your Hearing

You aren’t just imagining that you didn’t hear your boss’ instructions when you were in the middle of a yawn. Yawning actually does distort your hearing, at least temporarily, so that certain pitches and frequencies don’t reach your brain. Some people aren’t able to hear anything while they are yawning.

This happens because a tiny muscle inside your ear, called the tensor tympani, becomes activated when you yawn. It keeps you from messing up your hearing while you are yawning. So next time you can’t hear somebody amid a yawn, don’t be shy about asking the person to repeat what he or she said. You can even explain that your tensor tympani was activated so you couldn’t hear what was being said.

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27. Bad Company Can Corrupt Good Yawning

It turns out that you don’t just yawn contagiously when you hear someone that you are familiar with a yawn. You are less likely to yawn contagiously if you are surrounded by strangers and people that you are uncomfortable with, as opposed to people who are close to your social networks.

This may be because the social aspect of yawning can subconsciously make you feel vulnerable. If you aren’t willing to be vulnerable around certain people, that response may shut down. It may also be because the mirror neurons in your brain are much more likely to be activated when you are surrounded by those who are familiar to you.

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28. Crying While Yawning Is Completely Natural

Have you ever slipped a few tears when you were yawning and then found yourself quickly explaining to people that no, you aren’t crying? There’s no need to apologize or explain that you aren’t weeping. Your eyes may naturally secrete tears while yawning.

The lacrimal gland is inside your eye, with ducts that run in the space between your eyelid and eyeball. Yawning causes your jaw to squeeze the muscles that surround the lacrimal gland, which can force out tears. It’s an entirely natural response, so there’s no need to cry about it.

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29. Children With Autism Don’t Yawn As Much

Autism is a neurological condition that, among other things, is characterized by challenges with social behaviors and communication. Seeing as yawning actually is a social behavior and that it attempts to communicate something across a group of people, we shouldn’t be surprised that children (and adults) with autism don’t yawn as much.

There have been studies on autistic children to determine whether or not they yawn contagiously. When autistic children are around non-autistic children who are yawning, those with autism are much less likely to yawn in response.

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30. Not All Animals Yawn

If you have spent any time around cats and dogs, you know that they yawn quite a bit. After all, they are social creatures who are exhibiting one of the most primitive of all social behaviors. However, there are plenty of other animals that are also social but do not yawn.

Case in point: insects. They don’t yawn. Ever. But this isn’t because they are psychopaths (even though mosquitoes may be psychopaths). Insects don’t yawn because they don’t have central repositories, aka lungs, for collecting oxygen. However, they are still highly social creatures.

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31. Babies Yawn Before They Are Born

Few things have the “aww” factor quite as much as watching a newborn baby yawn. However, that first yawn that the parents see is not the child’s first; babies begin yawning in-utero. In 4-D resonance scans of fetuses, scientists previously believed that the babies were opening their mouths.

Nevertheless, in a study released back in 2012, scientists discovered that the babies were yawning. In fact, fetus yawns are twice as common as when they open their mouths. The yawns decrease in frequency after 28 weeks of gestation, which is about seven months into pregnancy.

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32. Yawning Indicates Fatigue

Behavior scientists are particularly interested in yawning as a social contagion, but that is far from the only reason why we yawn. You are far more likely to yawn when you are tired, whether you are by yourself or surrounded by other people.

When you yawn, your body energizes itself by consuming copious amounts of oxygen and releasing the toxic by-product of respiration, carbon dioxide. Beyond that, scientists aren’t entirely sure why fatigue leads to excessive yawning. Maybe you are just less likely to be able to resist the impulse when it strikes, but there are likely many explanations.

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33. Lack of Sleep Can Cause Excessive Yawning

Lack of sleep isn’t the same as fatigue. Fatigue is an acute feeling of drowsiness that isn’t always associated with sleep deprivation; you may be fatigued simply because you engaged in a heavy exercise session. Lack of sleep, or sleep deprivation, is going without proper sleep for an extended amount of time.

You may have sleep deprivation because of a sleep disorder, like sleep apnea. If you are yawning excessively, your body is probably trying to tell you that it is not firing on all cylinders. If that is the case, you may need to see your doctor and possibly a sleep specialist.

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34. Excessive Yawning May Be A Warning Of A Heart Attack

The vagus nerve is a critical cranial nerve that helps control the function of muscles and organs throughout the body. Internal bleeding, especially in your chest, can trigger your vagus nerve to cause you to yawn excessively.

In rare circumstances, you may yawn because the vagus nerve is attempting to tell your brain that a heart attack is imminent. If you are yawning excessively and are not fatigued or sleep-deprived, you should see a doctor to find out if something is going on. You should also make sure that you are familiar with the symptoms of heart attacks.

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35. Yawning May Be A Response To Medication

There is no shortage of physiological and behavioral explanations as to why we yawn. To add another to the repository, consider that certain medications, especially selective serotonin reuptake inhibitors (SSRIs), can also cause yawning. SSRIs increase the level of serotonin in the brain.

If you are on antidepressants, antihistamines, or some other medications, you may be more likely to yawn because of the SSRIs you are consuming. If you are on antidepressants, the extra yawning increases the effect of the medications, as the excess serotonin in your brain created by the yawning reflex helps to improve your mood.

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36. Excessive Yawning Can Also Indicate Epilepsy

Epilepsy is a condition that results from brain damage and causes seizures. The injury causes the brain to send out erroneous signals, which can include excessive yawning. While excessive yawning doesn’t automatically mean that you have epilepsy or another disorder, it does mean that you need to go to the doctor and get evaluated.

In addition to yawning, another neurological symptom that excessive yawning can indicate is a brain tumor or an impending stroke, particularly a stroke or tumor that is associated with the brain stem. Possibly the pressure on the brain stem stimulates a yawning response.

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