why yawns are contagious?
359903
they are not .Ever noticed In a crowdy place like in a movie hall when one person coughs or sneezes it start a chain reaction  thats because we deep in our concious know that it is agaist ettiqutes so when one person goes every other one gets an excuse.
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.
246554
Yes. The mere suggestion of yawning can induce a yawn in some people. (In fact I'm yawning right now from reading your question.) So if you sent an email saying "I'm yawning" to such a sensitive person, even if (s)he couldn't see or hear you that person could yawn.\nAlso, two people might yawn excessively if they shared an environment that is conducive to yawning, i.e., low in oxygen or high in carbon dioxide, but that wouldn't really be contagion.
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!
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!
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?
1178011
I know! why can't scientist study why yawns are so contagious?
17567
Yawning is one of those bodily mysteries that scientists haven't completely figured out yet.  The best theory I could find was that you yawn because you're not getting enough oxygen to the brain (maybe there is a lack of oxygen in the space you're standing).  Whenever you're aware of someone yawning, it activates a reaction in your subconscious mind that acts as a threat response.  Basically, whenever you see someone yawn, it makes you body think there is a shortage of oxygen too, and you yawn in response.  No one knows if this is actually the case, but I think that it is a good theory.
178925
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. This is sometimes referred to as "following the herd." Such people are sometimes labelled with the derogatory term "sheeple."\n\nSince the herding instinct includes both behavior and belief, the term 'herd behavior' describes only a part of this complex phenomenon in humans.
198710
When you yawn, you are attempting to take in as much air as possible, more oxygen gives more energy.  People in the immediate area are in competition for this air too and yawn as a response to retrieve air themselves
363390
The 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. 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). Ironically, 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.
239646
It's contagious to only those with an empathetic mind. Not everyone has one, so not everyone is going to yawn if someone else does.\n\nDon't listen to that Brisbane Roo character--he's full of it. It's true what he said about periods, but that has nothing to do with yawning.
462731
Cover your mouth if you want to, but it won't keep the next guy from "catching" your yawn.\nContagious yawning is real, scientists say, and it's "probably programmed into us," according to Dr. William Broughton, director of the Sleep Disorders Center at the University of South Alabama Knollwood Hospital.\n\nThe action of a mouth opening is not what compels others to yawn, Broughton said. Studies have demonstrated that showing someone a photo of a wide-open mouth does not induce a yawn.\n\nConversely, holding a hand over the mouth while yawning doesn't prevent it from being contagious, Broughton said.\n\nContagious yawns appear "basically to be a visual response," Broughton said.\n\nBetween 40 and 60 percent of people who watch videos or hear talk about yawning also end up doing the deed, according to Nature News Service.\n\nResearchers from the State University of New York in Albany tested people to find out why some are susceptible to contagious yawning and deduced that self-aware or empathetic people are more likely to catch yawns, according to the news service.\n\n"Identifying with another's state of mind while they yawn may trigger an unconscious impersonation....The findings also explain why schizophrenics, who have particular difficulty in doing this, rarely catch yawns," Nature News Service reported.\n\nBroughton said contagious yawning may be a social phenomenon, allowing groups of humans to coordinate their times of sleep.\n\nRonald Baenninger, a professor in the psychology department at Temple University in Pennsylvania, has studied yawning and said that the contagiousness is the part we know the least about.\n\nOne hypothesis is that the phenomenon came about when ancestral humans lived in troops, and it was important for them to wake up at the same time. Yawning may have been a way for them to communicate the level of alertness among different group members, Baenninger said.\n\nToday, contagious yawning is just the result of evolution, an instinctive action, Baenninger said.\n\nThough other creatures yawn - including dogs, cats and even snakes - contagious yawning is a "purely human occurrence," Broughton said. It begins around age 2.\n\nBaenninger and his students conducted a study to see if the contagion works between species. The students went to the zoo to observe whether humans would yawn when the animals did. A few people yawned in response to a lion's yawn, but the lion never replicated the humans' behavior, Baenninger said.\n\nThere is some evidence that when one ape yawns, others will too, the professor said.\n\nBroughton said it's not clear what causes yawns. He defined yawning as "slow, involuntary gaping movements of the mouth," and said the word is derived from the Old English word ganien, which means "to gape."\n\nSpontaneous yawning begins in the embryonic stage, so it is not learned behavior, Broughton said.\n\nThe idea of a fetus yawning while in the womb goes along with the notion of the action being a way to prepare for something, Baenninger said.\n\nYawning appears to be associated with sleepiness, though the idea that it has to do with boredom is not necessarily true, Broughton said. It's an unconscious effort to keep your alertness level elevated, Baenninger said.\n\n"I'm a professor. All professors are used to having students yawn at them," Baenninger said. But the yawns are an attempt to stay awake, rather than an affront, he said.\n\nA few notions about why we yawn have been debunked: "Because breathing takes in oxygen and removes carbon dioxide, theories in the past about why we yawn centered on the assumption that it was a reflex in response to low oxygen or high carbon dioxide levels," writes Dr. Robert H. Shmerling, an associate physician at Beth Israel Deaconess Medical Center and an associate professor at Harvard Medical School.\n\n"This theory lost favor
558756
As far as you should know yawning is contagious. Sorry I couldn't read that five-letter word you tried to put in it.
441827
See the article in the site below.  It tells you why we yawn and gives evidence to support the theory that yawning is "contagious" because "as social creatures we are highly inclined to copy one another."\n\nThe article starts by saying that a good trick to see if anyone is checking you out is to yawn and see if anyone else yawns back!  \n\nHope this helps...
792582
A yawn is in response to too much CO2 in the blood stream.  When you yawn there is a negative feed back loop in operation which tells the diaphram to contract (take a breath) because there is too much CO2......the yawn actually increases CO2.\nThe sneeze is due to irritation in the beginning of the respiratory tract, it expells such things as dust, bacteria and other irritants from your nose and sinuses.\nA hiccup is a sligh malfunction or mistiming if you will of the glottis which is a membrane that closes in your throat to prevent food from going into your lungs when you swallow.  Whenyou ge tthe hiccups it starts to close while you are taking a breath or expelling a breath.  It just takes a bit of time for your body to reset when it closes
40340
An indication of tiredness, stress, over-work or boredom. \nAn action indicating psychological decompression after a state of high alert. \nA means of expressing powerful emotions like anger, rejection or apathy. \n\nYou see someone yawning.  You hear someone yawning.  You read about yawning. You think about yawning. \nNow, you want to yawn. If this describes you, then you have just "caught" a yawn. Between 40 and 60% of the population is susceptible to contagious yawns, but the reason why yawns are catching is unknown. Steven Platek, Ph.D. suggests that being aware of one's own mental state ("self-recognition") and the ability to see things from another person's point of view ("mental state attribution") may make people susceptible to contagious yawns.