Why is Yawning Contagious?
Article Sources
- 1. Rundle, Brian K., et al. 'Contagious Yawning and Psychopathy.' Personality and Individual Differences, Pergamon, 5 June 2015, www.sciencedirect.com/science/article/abs/pii/S0191886915003645
- 2. Carey, Teresa. 'Why Are Yawns Contagious? We Asked a Scientist.' PBS, Public Broadcasting Service, 17 July 2018, www.pbs.org/newshour/science/why-are-yawns-contagious-we-asked-a-scientist#:~:text=What is known is that,imitate the actions of others
- 3. AC;, Massen JJ;Dusch K;Eldakar OT;Gallup. 'A Thermal Window for Yawning in Humans: Yawning as a Brain Cooling Mechanism.' Physiology & Behavior, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/24721675/
- 4. Norscia, Ivan, et al. 'Auditory Contagious Yawning Is Highest Between Friends and Family Members: Support to the Emotional Bias Hypothesis.' Frontiers in Psychology, Frontiers Media S.A., 3 Apr. 2020, www.ncbi.nlm.nih.gov/pmc/articles/PMC7147458/
- 5. Nahab, Fatta B. 'Exploring Yawning with Neuroimaging.' Frontiers of Neurology and Neuroscience, U.S. National Library of Medicine, 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC4041699/
- 6. Featured Neuroscience Psychology, May 22, 2018, et al. 'Why Do We Yawn and Why Is Yawning So Contagious?' Neuroscience News, 22 May 2018, neurosciencenews.com/yawning-contagious-9112/
- 7. St. Louis Public Radio | By Eli Chen. 'Contagious Yawning, Laughing and Scratching Gives Clues to How the Human Brain Works.' St. Louis Public Radio, 27 Mar. 2017, news.stlpublicradio.org/health-science-environment/2017-03-25/contagious-yawning-laughing-and-scratching-gives-clues-to-how-the-human-brain-works
- 8. 'Yawning: Causes and Reasons for Contagious Yawning.' Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/318414#Can-one-yawn-too-much
Yawning is such a common occurrence that people may not always think about why they're doing it. It's usually considered a sign that someone is tired or bored. But that's not the only reason people yawn. Sometimes people yawn not because they feel fatigued, but because they witness someone else yawning.
This is what's known as contagious yawning, and it may be triggered by someone who's nearby or even by watching a video of people yawning.1Rundle, Brian K., et al. ‘Contagious Yawning and Psychopathy.’ Personality and Individual Differences, Pergamon, 5 June 2015, www.sciencedirect.com/science/article/abs/pii/S0191886915003645 For some people, simply thinking about yawning may be enough to trigger it.
Why Do Humans Yawn?
It's not known exactly why humans yawn, but there are theories. People yawn when they're tired, bored or when someone else is yawning nearby. There may also be physiological reasons for yawning.
Some scientists think yawning may be related to breathing. A yawn brings in oxygenated air and quickens the heartbeat, which may be helpful when a person is drowsy and taking more shallow breaths.2Carey, Teresa. ‘Why Are Yawns Contagious? We Asked a Scientist.’ PBS, Public Broadcasting Service, 17 July 2018, www.pbs.org/newshour/science/why-are-yawns-contagious-we-asked-a-scientist#:~:text=What is known is that,imitate the actions of others Yawning may also help cool the brain. Inhaling air and speeding up the heart rate causes blood to circulate through the body faster, in turn, cooling the brain.3AC;, Massen JJ;Dusch K;Eldakar OT;Gallup. ‘A Thermal Window for Yawning in Humans: Yawning as a Brain Cooling Mechanism.’ Physiology & Behavior, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/24721675/ Yawns may also have evolved as a communication tool.
Spontaneous vs. Contagious Yawning
When people yawn spontaneously, they may throw their heads back and stretch their arms. These behaviors may help to cool the brain and get muscles ready for action. Brain temperature may be cooler after a yawn, according to recent studies.3AC;, Massen JJ;Dusch K;Eldakar OT;Gallup. ‘A Thermal Window for Yawning in Humans: Yawning as a Brain Cooling Mechanism.’ Physiology & Behavior, U.S. National Library of Medicine, pubmed.ncbi.nlm.nih.gov/24721675/
But the cooling brain theory only explains spontaneous yawns. Humans may have developed the ability to catch a yawn as a form of empathy. People are sometimes more likely to contagiously yawn around friends and family, rather than strangers, according to research.4Norscia, Ivan, et al. ‘Auditory Contagious Yawning Is Highest Between Friends and Family Members: Support to the Emotional Bias Hypothesis.’ Frontiers in Psychology, Frontiers Media S.A., 3 Apr. 2020, www.ncbi.nlm.nih.gov/pmc/articles/PMC7147458/
What Does Yawning Have To Do With Empathy?
Contagious yawning may occur more often in people with higher levels of empathy. People with low levels of empathy, such as those with autism, don't yawn contagiously as often. According to one study, participants who scored lower on a psychological test for empathy tended to yawn less in response to videos of people yawning.5Nahab, Fatta B. ‘Exploring Yawning with Neuroimaging.’ Frontiers of Neurology and Neuroscience, U.S. National Library of Medicine, 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC4041699/
Although research demonstrates a possible correlation between empathy and contagious yawning, it doesn't mean that not yawning in response to someone's yawn is a sign of autism or psychopathic behaviors.
Evolutionary History of Yawns
Yawning may be a leftover evolutionary trait that helped humans communicate before language was developed. Yawns may have sent a message of important information to the community.
When someone yawned, it may have signaled to the group that the person was tired or bored. This may have been critically important if the person yawning was responsible for guarding the group. When others in the group saw the person yawning, they'd know that someone else should take over sentry duty.6Featured Neuroscience Psychology, May 22, 2018, et al. ‘Why Do We Yawn and Why Is Yawning So Contagious?’ Neuroscience News, 22 May 2018, neurosciencenews.com/yawning-contagious-9112/
Other Contagious Nonverbal Behaviors
Yawning isn't the only nonverbal form of communication that may be contagious. Laughter, emotions, facial expressions and even scratching may also be contagious. Like emotions and other social cues, people may be compelled to imitate yawning when they see it.7St. Louis Public Radio | By Eli Chen. ‘Contagious Yawning, Laughing and Scratching Gives Clues to How the Human Brain Works.’ St. Louis Public Radio, 27 Mar. 2017, news.stlpublicradio.org/health-science-environment/2017-03-25/contagious-yawning-laughing-and-scratching-gives-clues-to-how-the-human-brain-works
Some scientists believe these behaviors helped the human species work together and convey important information before developing language. Scientists study these types of contagious behaviors to help understand the workings of the brain.
Contagious Yawning and the Brain
Oxytocin, a hormone associated with bonding, may have a role to play in contagious yawning, according to research.6Featured Neuroscience Psychology, May 22, 2018, et al. ‘Why Do We Yawn and Why Is Yawning So Contagious?’ Neuroscience News, 22 May 2018, neurosciencenews.com/yawning-contagious-9112/ When oxytocin was injected into various regions in rodents' brains, they began to yawn.
Yawning may be related not only to empathy but to stress. Cortisol may also trigger yawning.6Featured Neuroscience Psychology, May 22, 2018, et al. ‘Why Do We Yawn and Why Is Yawning So Contagious?’ Neuroscience News, 22 May 2018, neurosciencenews.com/yawning-contagious-9112/ Cortisol is a hormone associated with stress, and it may be why dogs tend to yawn during stressful situations, such as during visits to the veterinarian's office or when in the car.
Do All Animals Yawn?
All animals do yawn, including fish, birds and mammals, but they don't all experience contagious yawning. Yawning in animals appears to be more of a primitive reflex that's controlled by the brain stem. Interestingly enough, the bigger the brain, the bigger the yawn.
There are only two species that are known to catch yawns as humans do. These are canines and primates, and both are animals that experience empathy.8‘Yawning: Causes and Reasons for Contagious Yawning.’ Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/318414#Can-one-yawn-too-much
Can a Person Yawn Too Much?
Yawning is a normal behavior that typically doesn't cause any problems. However, it's possible to yawn too much. A rapid drop in blood pressure and heart rate called a vasovagal reaction also causes yawning. Yawning excessively may also be a symptom of several disorders.
Too much yawning can signify a sleep disorder, such as sleep apnea, a heart condition or a brain disorder. For example, excessive yawning may be related to certain heart defects and can even be a sign of a heart attack.8‘Yawning: Causes and Reasons for Contagious Yawning.’ Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/318414#Can-one-yawn-too-much
How To Prevent Excessive Yawning
Unless it's a symptom of an underlying disorder, there are ways to stifle yawns that seem to be occurring too often. Sometimes, the body may be yawning to try to bring in more oxygen. Taking some deep breaths through the nose to help increase the oxygen level in the blood can sometimes stop yawns.8‘Yawning: Causes and Reasons for Contagious Yawning.’ Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/318414#Can-one-yawn-too-much
If yawning is due to boredom or fatigue, getting up and moving may help end the case of the yawns.
When To See a Doctor
If someone suddenly experiences excessive yawning without a reason, it may be time to see a doctor. It may be due to a sleep disorder that's interfering with the person's ability to get a good night's sleep. Or, they may be experiencing one of the disorders listed above.8‘Yawning: Causes and Reasons for Contagious Yawning.’ Medical News Today, MediLexicon International, www.medicalnewstoday.com/articles/318414#Can-one-yawn-too-much
A physician may ask a person about their sleep habits and other symptoms to determine if their excessive yawning is due to fatigue, or something else.
