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Yawn

life science Maturity 7-9 Next article →

A yawn is a reflex found in almost all vertebrate animals. This group includes mammals, birds, reptiles, amphibians, and even fish.

Yawning Infant, August 2018
Yawning Infant, August 2018

Scientists who study yawning call this field chasmology. People often yawn when they are tired, bored, or hungry. It can also happen when a person feels stress. Sometimes, yawning is just a way the body reacts to things happening around it.

Oscar Bluhm Ermüdende Konversation crop
Oscar Bluhm Ermüdende Konversation crop

A yawn happens in a few specific steps. First, there is a long phase where the mouth opens wide. This is called the inspiratory phase. Next, there is a brief climax where muscles stretch. This part is called the acme. Finally, there is a rapid expiratory phase where muscles relax.

During this time, the airway can dilate to three or four times its original size. You might even hear a rumbling sound inside your head. This noise comes from the tensor tympani muscle in the middle ear. It is a mechanical noise rather than the sound of moving air.

Researchers have many theories about why yawning happens. One idea is that it helps control brain temperature. Mammalian brains work best within a very narrow temperature range. Another theory is that yawning helps animals stay alert. If a group of animals is drowsy, yawning might act as a signal to stay ready for danger.

Joseph Ducreux (French - Self-Portrait, Yawning - Google Art Project
Joseph Ducreux (French - Self-Portrait, Yawning - Google Art Project

Some scientists also think yawning helps stretch the muscles of the throat. This might help with swallowing, chewing, and making sounds. There are about twenty different psychological reasons that scholars have proposed.

Many studies have looked at how yawning spreads from one person to another. This is called contagious yawning. It is a type of echopraxia, which is when you imitate an action.

Edgar Germain Hilaire Degas 084
Edgar Germain Hilaire Degas 084

A 2011 study by Ivan Norscia and Elisabetta Palagi found that social bonding is very important. People are most likely to catch a yawn from family or friends. They are less likely to yawn for strangers. This behavior has also been seen in chimpanzees, dogs, and cats. Even different species can sometimes trigger a yawn in one another.

Some people believe contagious yawning is linked to empathy. Empathy is the ability to understand how others feel. Research by Garrett Norris suggests that yawning shows an appreciation of another's state. For example, dogs can catch yawns from humans. A study from the University of London showed that 29 dogs were tested. Twenty-one of those dogs yawned when a stranger yawned. This shows how animals can read human communication. Even in art, yawning is a part of life.

Joseph Ducreux (French - Self-Portrait, Yawning - Google Art Project
Joseph Ducreux (French - Self-Portrait, Yawning - Google Art Project
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🖼️ Images & Media (5)
Fetal yawning 4D ultrasound ecografia 4D...
File:Yawning Infant, August 2018.jpg
Yawning Infant, August 2018.jpg
File:Edgar Germain Hilaire Degas 084.jpg
Edgar Germain Hilaire Degas 084.jpg
File:Joseph Ducreux (French - Self-Portrait, Yawning - Google Art Project.jpg
Joseph Ducreux (French - Self-Portrait,...
File:Oscar Bluhm Ermüdende Konversation crop.jpg
Oscar Bluhm Ermüdende Konversation crop.jpg
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