Are yawns really contagious?
Weve all caught yawning from other people, but why that happens is unclear, according to a psychologist who has researched the behavior. In short, we dont know why yawns are contagious, said Meredith Williamson, a clinical assistant professor at Texas AM College of Medicine. Researchers used to think that yawning was only signaling a need for sleep, but now they believe that it can communicate a shift in alertness or boredom.
One theory is that contagious yawning is related to empathy, and that people with higher levels of empathy yawn more often when someone else yawns, compared to people with lower levels of empathy or those with a mental disorder. Researchers have seen that yawning may not be as contagious to people with autism or schizophrenia, Williamson said in a university news release. More research is being done to determine the cause of this.
She also noted that children under the age of 4 and older adults are less likely to yawn in response to somebody else yawning.
Yawning may be an unspoken form of communication, but its not unique to people, Williamson added. Some species of primates and canines yawn in response to each others yawns, and dogs will even yawn after a person yawns.
Yawning is multifactorial. It could be partly an innate form of communication or it could be related to empathy, or a bit of both combined with other factors, she suggested. A yawn is an involuntary reflex where the mouth is opened wide, and the lungs take in a lot of air. The air is then exhaled slowly. During this time, the eardrums stretch, and the eyes may also close tight, causing them to water.
No thought or action has to be taken to produce a yawn, and the process is similar for everyone. Yawning commonly occurs either before or after sleep, which is why it is usually considered a sign of being tired. Yawning also occurs frequently in people who are doing boring or tedious things.
There is also a social aspect to yawning. Yawning appears to be contagious among humans and other animals, and the contagiousness of a yawn is well documented but hardly understood.
Fast facts on yawning
Here are some key points about yawning. More detail and supporting information is in the main article.
There is no definitive reason for a yawn yet. Many proposed theories have surfaced and been studied, and they provide some clues.
Yawning is commonly thought to be a sign of sleepiness or boredom, though this is not always the case.
While someone who yawns may be tired, the heart rate quickly rises during a yawn. This increased heart rate suggests yawning can be a sign of alertness rather than sluggishness.
Yawning, in general, may simply be a way for the body to change the state of awareness it is in:
People may also yawn when changing physical states as well, such as moving from an area of high pressure to low pressure. This pressure can build up in the eardrums and may cause the person to yawn to release it. Yawning may be a function of breathing. Yawns may be more likely when the blood needs oxygen. A yawn causes a big intake of air and a faster heartbeat, which could theoretically mean that it is pumping more oxygen through the body. So a yawn may be simply designed to help clear toxins out of the blood and provide a fresh supply of oxygen.
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