why is yawing contagious?
406589
One theory says that it is a vestige of the group behavioural aspect of human evolution. This theory was put forth following observations of communal yawning in apes. The leader in an ape group yawns, and the rest follow suit. \n\nApart from the theories, consider this: \nTo some extent, yawning is indicative of one's state of mind, and can be physiologically linked to cerebral activity. It usually comes when all novelty in an idea or concept being explored has been temporarily exhausted. So it may happen that when an idea is being explored in a group, a statistical majority would always hit a 'low' (or an intellectually lean) patch in the exploration simultaneously . Hence yawning results. \n\nThe other type of yawning is when there is no group activity involved, and one yawns just by looking at another person yawning. This has to do with empathizing, as has been explained.
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.
428835
Yes giggling can be contagious.  \nYes laughing is good for you.\n\nI was at a jazz club last night, and my friend had a funny picture of her cat.  It was hilarious.  We laughed so hard, you know the belly-laugh.  A few other people who saw the picture of the cat joined us laughing.  Then a man takes a look at the picture, and he just stares at it then looks at us like we're all crazy, which made us laugh even harder.  So, yes, many of us caught the giggle bug, and the one escaped it.
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.
401246
NO!  Laryngitis itself is not contagious but if you got the laryngitis due to a cold, the cold is contagious....as you know. \n\nLaryngitis is an inflammation of the voice box, or larynx, that causes your voice to become raspy or hoarse. It can be short-lived or long-lasting. Most of the time, laryngitis comes on quickly and lasts as long as two weeks.  \n\nLaryngitis is caused by:\nan upper respiratory infection, especially a cold or flu. \nStraining or overusing the voice\nAllergies\nExposure to irritants, such as smoke or chemicals. \nGastroesophageal reflux disease
1002474
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".
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.
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.
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).
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!
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.
329034
We yawn because of a lack of Oxygen. Think about it: when you yawn more air comes in and sometimes after a yawn you feel rejuvenated for a little while. But this is contagious because if you yawn you are probably in an Oxygen-deprived environment and everyone around you is going through the same lack of Oxygen. And yawning is related to sleep because when you're asleep you're barely doing more than breathing, beating your heart and dreaming which doesn't take up much oxygen but you still get the same amount of oxygen as you would awake in the same room so there's more oxygen to relax your brain and mind and everything else that might be tired.
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...
337591
because yawns are catching and a yawn is when you are tired and need a hugeee gulp of air so of course if someone in your group has yawned and inhaled alll the air then you nearly suffocate cause you've got no air so you have to yawn to try get some air before you collapse. so blame you friends for snatching the air from your lungs making you yawn !!!!!!!!!!!!!!!!!!!!
662014
This came up in my sister's wildlife biology class--in the wild, animals that live in herds do something similar to a yawn when everything is peaceful and there is no danger lurking (like lions), and the yawn passes from one animal to the next as a signal.  Apparently the biological urge is in humans as well--maybe we are passing along that we are relaxed and not feeling threatened.
196592
It is the brain requiring more oxygen. Which is why when someone else yawns you do to, it is your brain making sure that it has enough in case the other person takes it all. Not very likely to happen unless in a confined space, but the brain is always on survival mode.
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