Why do people sometimes spit when yawning?
371652
In general, gleeking occurs when excessive saliva accumulates in the mouth (due to stimulation of the sublingual gland) and is propelled out as a stream or mist through the narrow gap between the maxillary central incisors. This may occur accidentally (e.g. while talking, eating, or yawning) but may also be the result of deliberately forcing the saliva out via a subtle action involving strategic interplay between the tongue and lower jaw. This action is a learned skill; like ear wiggling, not everyone can do it. One popular method is to press the underside of the tongue against the palate, then push the tongue forward while pulling the lower jaw slightly backward. Another method is to yawn deeply, and then press the tongue against the palate. This method is usually more successful, but is also more obvious.
261027
Why is this the second most asked question on here?  If the guys would stop asking about the size of their "manhood", this would be number one!\n\nWhy we yawn when we see others yawning has baffled scientists for ages and a number of suggestions have been put forward to explain this phenomenon. What we do know is that yawning is an involuntary action- our brain does it without us thinking about it, even very young babies yawn showing that it's a built in action (Chimps do it too by the way). Just thinking about yawning can trigger the bit of the brain that causes a yawn. http://www.ratlab.co.uk/yawn.htm...\n\nMore theories can be found at the links below: \n\nhttp://www.world-science.net/exclusives/...\nhttp://www.yesmag.bc.ca/questions/yawn.h...
220911
Why is yawning infectious? \n\nGemma Martin, London UK\nWhen you yawn, you equalise the pressure in your middle ear. This causes a small, localised pressure change around you, which affects others in the vicinity - and therefore they have to yawn to equalise the pressure in their own middle ears. \n\nJoe Lambert, Norwich, England\nIt's a left over mechanism from our days as troupe creatures. Infectious yawning meant that we slept togther as a group when the most tired required to sleep. \n\nPeter Brooke, By Kinmuck Scotland\nIn 1990,in Guardian Notes and Queries vol.1, an answer was that it was part of a mechanism to "synchronise wake/sleep cycles" among people in a social group, and that yawning is poorly understood. I don't know if progress has been made since then. \n\nivor solomons, norwich england\nThis applies only to group/troupe animals. It supplies a method for the most sleepy to forcefully communicate their need for rest and thus ensures that the group rests/sleeps together. \n\nPeter Brooke, By Kinmuck, UK\nYawning is essentially a reflexive method of increasing oxygen intake. Oxygen intake in this manner is primarily used as a means to stay alert. When we observe others yawn it triggers a warning to ourselves that we are in a situation where we need to be alert, hence the infectious desire to yawn yourself. \n\nAndy Preston, Otley, UK\nIf you accept the theory that yawning is related to breathing, as a means to either redistribute lung surfactant or to temporarily increase air intake, it may be that watching someone yawn triggers a subconcious concern about one's own ability to breathe, hence mimicking the yawn. Alternatively, it may be a throwback to primate warning signs, which involve displaying of teeth when threatened. The common response to this is a reciprocal baring of teeth. \n\nBrendan O'Sullivan, Birmingham, UK\nThere is no one answer to this question, other than unsatisfying ones like "because we evolved that way". Or more accurately, some species in our distant past evolved that way (if you yawn at a dog, it will often yawn back, and chimpanzees also exhibit contageous yawning). Yawning might help communicate to other members of a group that it's time for everyone to settle down for a snooze, but (like laughing and frowning), it's hard to explain why this particular behaviour should represent this meaning. \n\nAllan Dean, Wimbledon \nI've heard it's because when the alpha male in the group of apes (which turned into us)had checked everything out and knew it was safe to sleep he would yawn to other apes, as a message that all was safe, and they in turn would yawn the message through the group, so it's instinctive. \n\nDonna Thomas, Bristol, UK\nIt's because you're afraid that other people are stealing your air \n\nJimmy, Ceredigion, Wales\nSteven Platek, a professor of cognitive neuroscience at Drexel University in Phildelphia, has carried out research correlating the "echoing" of yawns with the empathetic response of the individual. In other words it is a kind of social response, and those deficient in the ability to make emotional bonds (schizotypal individuals) are less likely to yawn back. \n\nTony Dunlop, Zeal Monachorum, England
222830
There could be a multitude of reasons. Yawning is caused by a lack of oxygen to the lungs. You yawn because it allows an immense amount of oxygen to your lungs.
330313
This is science.\n\nWhen you yawn, it is because your brain lacks oxygen and need to get more oxygen. This is done by yawning where you inhale deeply to take in more air and oxygen. \n\nWhat you mentioned is especially true, especially in crowded places or enclosed palces.\n\nWhen you yawn, you take in large amount of air from the surrounding, depriving the other of the oxygen. Thus, the others will need more oxygen too. So, they yawn to take in more air. And when they yawn, they take in even more air from the surrounding and the others will have to yawn to get sufficient oxygen.\n\nOne yawn will spark off a chain reaction of yawning.\n\nUnderstand now?
373477
Yes, it is rude to yawn while someone is speaking. I especially hate those who make those loud noises and they have their mouths wide open. It gives a message to the speaker that he/she isn't good enough or is boring. When people can't control their yawn, they should at least do it discreetly and  cover their mouths.
532727
A yawn is a reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or from boredom.\n\nYawning is a powerful non-verbal message with several possible meanings, depending on the circumstances. It is also claimed to help increase the state of alertness of a person.\n\nCauses 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. \n5. 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.\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
202412
THE TRUTH IS that we don’t completely understand why people, or animals for that matter, yawn. It’s widely assumed that yawning occurs because we are tired or bored or because we see someone else doing it, but there isn’t any hard evidence to support these beliefs.\n\nThe most plausible explanation, and the one that is taught in medical school, is that we yawn because oxygen levels in our lungs are low. \n\nStudies 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.\n\nBut 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.\n\nAnother 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).
272413
It is an instinctual social response.  Yawning signals to others in the social group that it is time to rest.
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."
607567
Urge to yawn on seeing someone else yawn is called reflex yawning. When you see someone else yawn, it sends a message across your brain that you also need more oxygen and as a response your open your mouth wide in an attempt to get in more air and your lungs expand (i.e you yawn).
449198
Not contagious but we are affected by an others yawning. This is called "Alolomimea" funny name but its what its called. Scientists believe that the reason we react to other people yawning is because in our early history ("caveman times") we needed to regulate our sleeping patterns so we could all survive together. Kinda like one for all and all for one deal. So if one of our cavemen buddies was tired we would all need to rest so we could all effectively hunt as a unit. It served  us as a natural "hey dude im tired lets take a break so we can hunt better and not die" It's a true story!
378590
People yawn when the level of carbon dioxide in their blood is a little too high, this is bad and eventually can cause unconsciousness.  To stop this you yawn, yawning means you take in a big gulp of oxygen and expel carbon dioxide.  They are thought to be contagious because if I see you yawning my brain thinks.. uh oh there is too much carbon dioxide in this room that person is already feeling the effects, to protect myself I will yawn too!\n\nBy the way you also yawn if you're tired because you're breathing naturally slows which makes carbon dioxide build up more easily.  You will yawn when you are tired to expel this excess carbon dioxide!
337667
It's a psychological reaction.  You see someone yawm and then your brain wants you to yawn too.  For some reason I always want to yawn when I go down the back stairs at work.\n\nIt's the same way smoke makes some people want to cough.  Theatrical smoke is not suppose to make you cough, but every play I've seen with smoke people in the audience aways start coughing.\n\nDifferent conditions cause your body to react in different ways without you have to think at all about it.
375489
Virtually any stimulus associated with yawns -- including viewing, reading about, and even thinking about, yawning -- evokes yawns. (Are you yawning yet?) Yawning spreads in a chain reaction through a group, a compelling example of human herd behavior and a reminder that we are not always in conscious control of our actions. The urge to replicate an observed yawn is clearly an automatic response triggered by our brains.\n\nStudies partially explain the reason for yawning. Although we yawn more when sleepy or bored, it is unclear whether yawning increases alertness. And scientific evidence refutes one of the most popular myths of yawning? that it happens in response to low oxygen or high carbon dioxide levels in the blood or brain. Test subjects do not yawn more when breathing air with enhanced levels of carbon dioxide nor do they yawn less when breathing pure oxygen. One fact explains a lot of apparently inconsistent data. People yawn most during behavioral transitions, such as just after waking and shortly before bedtime. Yawning may help facilitate those changes. Contagious yawning may synchronize a group's behavior so that, for instance, a whole family goes to sleep together.
142620
No..A yawn is something your body does when it needs a little more oxygen. Like if you were in a small area your body will yawn to get as much oxygen it can and remove the carbon dioxide .. all you have to do is take a deep breath and go about your business..
207785
Next to questions that males ask regarding the size of their manhood, this has to be the second most asked question here!\n\nWhy we yawn when we see others yawning has baffled scientists for ages and a number of suggestions have been put forward to explain this phenomenon. What we do know is that yawning is an involuntary action- our brain does it without us thinking about it, even very young babies yawn showing that it's a built in action (Chimps do it too by the way). Just thinking about yawning can trigger the bit of the brain that causes a yawn. http://www.ratlab.co.uk/yawn.htm...\n\nMore theories can be found at the links below: \n\nhttp://www.world-science.net/exclusives/...\nhttp://www.yesmag.bc.ca/questions/yawn.h...