Why do we yawn? and why is it so contagious?

Question

I've heard a few theories i.e its evolutionary, the brain needs more oxygen but i dont kno.

Answer 1

Causes of yawning

An indication of tiredness, stress, over-work or boredom.

An action indicating psychological decompression after a state of high alert.

A means of expressing powerful emotions like anger, rejection, apathy or tedium.

A yawn can express strong anti-social messages, and so in some cultures people try to mute or mask them by placing a concealing hand over the yawning mouth.

A long-standing hypothesis is that yawning is caused by an excess of carbon dioxide and lack of oxygen in the blood. The brain stem detects this and triggers the yawn reflex. The mouth stretches wide and the lungs inhale deeply, bringing oxygen into the lungs and hence to the bloodstream. It is almost certain however, that this hypothesis is not correct. One study documented that this effect does not exist ("Yawning" by Robert R. Provine, pages 532-539, American Scientist, November-December 2005, Vol 93, No. 6). [1]. A more recent hypothesis is that yawning is used for regulation of body temperature. Another hypothesis is that yawns are caused by the same chemicals (neurotransmitters) in the brain that affect emotions, mood, appetite and other phenomena. These chemicals include serotonin, dopamine, glutamic acid and nitric oxide. As more of these compounds are activated in the brain, the frequency of yawning increases. Conversely, a greater presence in the brain of opiate neurotransmitters such as endorphins, reduces the frequency of yawning. Patients taking the serotonin reuptake inhibitor Paxil (Paroxetine HCl) have been observed yawning abnormally often. Another theory is that yawning is similar to stretching. Yawning, like stretching, increases blood pressure and heart rate while also flexing many muscles and joints. It is also theorized that yawning helps redistribute an oil-like substance which coats the lungs and aids breathing. Some have observed that if you try to stifle or prevent a yawn by clenching your jaws shut, the yawn is unsatisfying. As such, the stretching of jaw and face muscles seems to be necessary for a good yawn.


The yawn reflex is often described as contagious: if one person yawns, this will cause another person to "sympathetically" yawn.[2] The reasons for this are unclear; however, recent research suggests that yawning might be a herd instinct.[3] Other theories suggest that the yawn serves to synchronize mood behavior among gregarious animals, similar to the howling of the wolf pack during a full moon. It signals tiredness to other members of the group in order to synchronize sleeping patterns and periods of activity. It can serve as a warning in displaying large, canine teeth. This phenomenon has been observed among various primates. The threat gesture is a way of maintaining order in the primates' social structure. The contagion of yawning is interspecific (i.e., try yawning in front of your dog). Yawning in public is generally regarded as impolite in the West, but came into fashion in polite French society for a brief period in the late 18th century. Oddly, sometimes sympathetic yawning may be caused by simply looking at a picture of a person or animal yawning, or even seeing the word "yawn".

Adelie Penguins employ yawning as part of their courtship ritual. Penguin couples face off and the males engage in what is described as an "ecstatic display," their beaks open wide and their faces pointed skyward. This trait has also been seen among Emperor Penguins. Researchers have been attempting to discover why these two different species share this trait, despite not sharing a habitat.

Answer 2

Notice when you yawn you inhale, not exhale. It is a fast way for your body to take in oxygen. You yawn when you are tired, no? Fatigue and the feeling of tiredness occurs because there is not enogh oxygen in the blood cells for the body to function optimally. Hence your brain sends out this message and it is a kind of "relex" that makes you yawn to take in a large amount of O2.

I believe it is contagious because when you see someone yawn your brain sends out the message (as above) that your body, too, could do with more oxygen

Answer 3

The most plausible explanation, and the one that is taught in medical school, is that we yawn because oxygen levels in our lungs are low. Studies have shown that during normal, at-rest breathing, we don’t use anywhere near our lung capacity; for the most part, we just use the air sacs at the bottom of the lungs. If the air sacs, called alveoli, don’t get fresh air, they partially collapse and the lungs stiffen a bit. As a result, it’s believed, our brain prompts the body to either sigh or take a yawn to get more air into the lungs.

But certain aspects of yawning remain even more mysterious. Fetuses, for instances, have been observed yawning in the womb, yet it’s known that they don’t take oxygen in through their lungs. And yawning seems to be a symptom of multiple sclerosis and other medical conditions, for reasons unclear.

Another puzzling phenomenon is that some male animals, men included, yawn in association with penile erection (although it’s presumptuous to assume they’re bored with their sex lives).


ha lol hope this helps =)

Answer 4

it is to get more oxygen to the brain i dont know why it is cotagious but i have read in a book of 100 thing s to do during a boring sermon to yawn and see what happens it works

Answer 5

the oxygen. And because you need to sleep and get the brain started working

Answer 6

the reason we yawn is with the aid of fact our respiratory slows inflicting a loss of oxygen and so we yawn to take up a deep breath, this is why we yawn as quickly as we are drained-our respiratory slows down. And as quickly as we see somebody else yawn our respiratory slows down somewhat back so we yawn :)

Answer 7

because we have excessiv carbon dioxide in our lungs, yawning expells it.

It is contagious because when we expell the carbon dioxide, the other people breathe it in, giving them excessive carbon dioxide
or
because one person sets the rythm of breathing and if one isn't breathing deeply enough neither is their neighbor(by proximity) and so both need to yawn, just one may yawn first. sometimes the yawn is at the same time

Answer 8

Nobody knows for sure, most views are linked to evolution, some people think it is to get more oxygen in our brains or to alert us when getting too sleepy

Answer 9

yes its the bodies way of getting oxygen to the brain

Answer 10

it's because all the bacteria on the back of your mouth have stretched out to push your mouth open. those suckers are strong, so you can't resist them, no matter how hard you try. what they are doing is allowing their brothers, sisters, and cousins to escape because they are trying to rule the world. if they jump into someone's mouth nearby, you'll know it because they'll prop their mouth open too.

it's pretty scary how we are trying to stop global warming, and the whole while we are all going to be taken over by bugs that are going to control everything anyway.