why are yawnings contagious?
537048
Because according to psychology, they are sympathetic responses.  Its funny that in a test, people who didn't yawn after seeing others yawn were found to be anti-social.
1170939
From what I've read, we are not sure exactly why that happens, but many doctors and scientist believe is is due to a mental reaction that sees a person yawn and believes you should do so as well.  Yawning is a response to a lack of oxygen in the brain under idle conditions, such as standing around or sitting in a chair.  So when you see someone yawn, your brain triggers a yawn to make sure you are also not starving your brain.
967357
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."\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?
1005855
(1)"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."\n\n(2)  "Professor Andrews told Scientific American yawns may be contagious because we human animals are trying to communicate changing environmental conditions to others, possibly as a way to synchronize behavior. Obviously, this would be one of those caveman-type mechanisms that is no longer needed that our bodies remember and still do.\n\nWhen we yawn, we draw in more oxygen and remove a build-up of carbon dioxide. Larger groups produce more carbon dioxide. So one theory holds that we yawn when we're in large groups of people to purge the carbon dioxide--and in so doing, we set off a chain reaction. But Robert Provine, a psychologist at the University of Maryland, Baltimore County, tested the theory and says it's bunk. Giving people additional oxygen didn't decrease yawning and decreasing the amount of carbon dioxide in a subject's environment also didn't prevent yawning, notes the How Stuff Works Web site.\n\nWhatever the reason for yawns being contagious, How Stuff Works reports that 55 percent of people will yawn within five minutes of seeing someone else yawn. In addition, blind people will yawn after hearing others yawning. And we're sure that reading and writing about yawns is enough to induce one!"
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?
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!
289289
Between 40 and 60% of the population is susceptible to contagious yawns, but the reason why yawns are catching is unknown.\n\nI yawned once when typing up this answer.
85551
I think this deserves to be a featured question.  Here are a few theories and a link below:\n\nEverybody yawns - from unborn babies to the oldest great-grandparent. Animals do it, too. But why, exactly, do people and animals yawn? No one knows for sure. But there are many theories (ideas) about why people yawn. \n\nOne is that when we are bored or tired, we just don't breathe as deeply as we usually do. As this theory goes, our bodies take in less oxygen because our breathing has slowed. Therefore, yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood.\n\nYawning, then, would be an involuntary reflex (something we can't really control) to help us control our oxygen and carbon dioxide levels. Sounds good, but other studies have shown that breathing more oxygen does not decrease yawning. Likewise, breathing more carbon dioxide does not increase yawning. Hmmm. Now what?\n\nAnother theory is that yawning stretches the lungs and lung tissue. Stretching and yawning may be a way to flex muscles and joints, increase heart rate, and feel more awake.\n\nOther people believe that yawning is a protective reflex to redistribute the oil-like substance called surfactant (say: sur-fak-tunt) that helps keep lungs lubricated inside and keeps them from collapsing. So, if we didn't yawn, according to this theory, taking a deep breath would become harder and harder - and that would not be good!\n\nBut there is one idea about yawning that everyone knows to be true. It seems contagious. If you yawn in class, you'll probably notice a few other people will start yawning, too. Even thinking about yawning can get you yawning. How many times have you yawned while reading this article? We hope not many!
325601
Professor Andrews told Scientific American yawns may be contagious because we human animals are trying to communicate changing environmental conditions to others, possibly as a way to synchronize behavior. Obviously, this would be one of those caveman-type mechanisms that is no longer needed that our bodies remember and still do.\n\nWhen we yawn, we draw in more oxygen and remove a build-up of carbon dioxide. Larger groups produce more carbon dioxide. So one theory holds that we yawn when we're in large groups of people to purge the carbon dioxide--and in so doing, we set off a chain reaction. But Robert Provine, a psychologist at the University of Maryland, Baltimore County, tested the theory and says it's bunk. Giving people additional oxygen didn't decrease yawning and decreasing the amount of carbon dioxide in a subject's environment also didn't prevent yawning, notes the How Stuff Works Web site.\n\nWhatever the reason for yawns being contagious, How Stuff Works reports that 55 percent of people will yawn within five minutes of seeing someone else yawn. In addition, blind people will yawn after hearing others yawning. And we're sure that reading and writing about yawns is enough to induce one!
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?
609665
Because they trigger the receptors in the brain to relax.  Yawning signals relaxation to other humans, thus causing themselves to inadvertantly yawn.  It's like human relation reflex.
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.
347438
It's a subconscious thing.  When a person is yawning, their body is sensing that it is not getting enough oxygen.  Something in our subconscious sets off, and causes us to yawn when we see someone else do it.
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
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.
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.
213862
Why 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: