Why do we automatically cover our mouths when we yawn?
396103
If i remember correctly the origin is that when you yawn people believed that demons would get inside of you if your mouth wasn't covered.
309172
padillio is right. it is just a mental thing, and she is also right in saying that it is because of a lack of oxygen. it is also associated with being tired b/c when you're body is fatigued or tired, you're breathing slows down and you get a lack of oxygen. yawning is an involuntary muscle movement to make you breath heavily and take in more oxygen. anyway, that's pretty much it.
562180
During periods of inactivity, our muscles become more susceptible to fatigue. Stretching after periods of rest increases circulation through the muscles, delivers much needed oxygen, and warms the muscles up to prepare them for activity. Not only do we automatically feel the need to stretch after sitting for a while, it is wise to stretch the muscles more thoroughly before beginning any strenuous activity or exercize in order to prevent from pulling or tearing the muscles.\n\nAs for yawns, we do that for about the same reason: to increase circulation by letting in more oxygen.
288559
A yawn is a reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or from boredom. \n\nThe yawn reflex is often described as contagious: if one person yawns, this will cause another person to "sympathetically" yawn. The reasons for this are unclear; however, recent research suggests that yawning might be a herd instinct.\n\nHerd instinct\n------------\nThe so-called herding instinct is a social tendency in humans to identify with and model many behaviors and beliefs after a larger group of individuals with whom they identify.\n\n\nOther 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, thus proclaiming, "don't attack while I am sleeping...
766538
Yawning individuals are exposed to the same atmospheric oxygen concentration this could fall marginally to set off the masseteric reflex to pump more blood to the brain from within the masseter muscles,so when this happens it appears to be contagious.
394382
Yawns are contagious because people naturally emulate what they see others doing. For more, read a section in the Tipping Point by Malcom Gladwell.
56869
The answer is, no one really knows why yawning is "contagious". Or why we yawn at all. One popular explanation is that yawning allows you to get rid of too much carbon dioxide in your system and increase your oxygen supply. This was disproved by Dr. Robert Provine and his research team in 1987.\n\nNow scientists are wondering if yawning is from our deep past -- part of our evolutionary history. Did a yawn signal to the group that it was time for everyone to retire to the trees and snooze? Did a yawn signal that we were all feeling cozy and warm about each other? Did a yawn signal something more like, "Gee, I know how you're feeling, I feel that way too."
226680
Because when someone else yawns, it pops your ears. So to pop them back, you yawn. \n\n*No, I'm not making this up. Really. I saw it on Beakman's World when I was like ten. I just have a freaky memory.*
632459
Causes of yawning\n1.An indication of tiredness, stress, over-work or boredom. \n2.An action indicating psychological decompression after a state of high alert. \n3.A means of expressing powerful emotions like anger, rejection or apathy. \n4.A sign that one is not breathing deeply, and not receiving enough oxygen through the body. \nA 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.\n\nA 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). 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.\n\nAnother theory is that yawning is similar to stretching. Yawning, like stretching, increases blood pressure and heart rate while also flexing many muscles and joints. 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.\n\nThe 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, thus proclaiming, "don't attack while I am sleeping..." 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".\n\nAdelie 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.
64755
Personally, I think it's a sub-conscience action since you don't have to be aware of someone else yawning. Think of it this way, you weren't hungry until you saw, smelled, or someone mentioned food. So as you idle your body equates lack of action as rest. As we all know, rest is equated to sleep, so your idle body wasn't tired until someone yawned. \n\nI know it sounds odd but, have you ever yawned while your cardio system was working harder than compared to sitting idle?
1078201
This question has taken me a super long time to answer -- I've spent much of the time yawning every time I try to research! It's true! Are you yawning yet? Humans yawn when they see someone else yawn, read about yawning, think about yawning, or even just hear yawning. I can barely keep my hands on the keyboard because once I yawn, I tend to stretch and then rub my face.\n\nThe answer is, no one really knows why yawning is "contagious". Or why we yawn at all. One popular explanation is that yawning allows you to get rid of too much carbon dioxide in your system and increase your oxygen supply. This was disproved by Dr. Robert Provine and his research team in 1987.\n\nNow scientists are wondering if yawning is from our deep past -- part of our evolutionary history. Did a yawn signal to the group that it was time for everyone to retire to the trees and snooze? Did a yawn signal that we were all feeling cozy and warm about each other? Did a yawn signal something more like, "Gee, I know how you're feeling, I feel that way too."\n\nBetween 40 and 60 percent of the population seems to find yawning contagious. Researchers at the State University of New York conducted a series of yawning experiments. They determined that being self-aware (the ability to recognize oneself) and having the ability to see things from someone else's viewpoint means a person is more likely to find yawning contagious.\n\nNow you're thinking, what humans are not self-aware? Schizophrenics sometimes have trouble with self-recognition so they will not find yawning contagious. Babies won't yawn contagiously until they're more than a year old.\n\nSome birds and reptiles yawn. Most mammals yawn. My dog yawns, but that doesn't make me yawn -- I obviously cannot put myself in her paw prints. (But who can empathize with a creature that sleeps all day, then when she does bother to get up and join you on a walk, suddenly bolts after a squirrel and nearly tears your arm out of your socket? I have no idea what's going on in that dog's mind.)\n\nChimpanzees yawn too, and in fact, if they watch other chimps yawn, they're more likely to yawn too.\n\nSo, I guess the real answer is: who knows?
680125
Here's a theory. Yawning can be caused by lack of oxygen, and if a bunch of people are in the same room which is poorly ventilated (no windows open, no air conditioning, or it's a stiflingly hot room) they could all yawn because of this, as they are all in the same place.\n\nEither that or they are all tired! :D
345712
It is herd behavior, it signals when the herd needs to move on to something else. When one person yawns, it is passed along to 'pass the message.'
317540
A Yawn is the brain's natural way of rapidly increasing the amount of oxygen taken into the lungs for use by the body during times of fatigue. It is triggered by very delicate mental cues and accordingly, can be triggered by seeing someone else yawn or even thinking about yawning long enough.
635799
1. because your body needs oxygen\n2. becaus you are bored and it is a way for your body to tell you to do something else\n3. becaus other people yawn. it is a social behavior that makes a group "stay together" \n\nhow? not sure, but I think your brain open your mouth and make your lungs draw in lots of air without letting you know first.
262175
science are baffled why yawning is contagious. They have none whatsoever for explaining this phenomena. However psychologies insists it is psychological.
276956
When working out the blood flow is increased to the working muscles. As a result there is less blood and oxygen flowing to the brain triggering the yawn. This is your body's way of increasing the oxygen level in the brain to compensate.\nAs your body accomodates the increased physical demand, the yawning should become less.