Why are yawns contagious?
435953
It's not that they are contagious.  Its just that people yawn because their brain isn't getting enough oxygen and when someone sees another person yawning they....yaaaaaaaawwwwnn.  And then another person sees THEM yawning and they think, "Hey, maybe MY brain needs more O2.  I think I'll just Yaaaaaaaawwwwn.  And then another person sees them yawning and they think, "Oh no, I don't have time to Yaaaaaaaaaawwwnnn."  And then another person sees them yawn and they sa...yaaaaaaaaaawwwwn.  I think this answer is making me sleepy.  Good night.
480001
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.
361765
Not really sure---but just seeing the word yawn made me yawn--Thanks alot---yawns again---wonders about yawns--yawns again-- http://en.wikipedia.org/wiki/Yawn Why are yawns contagious? Getting kind of tired-- http://www.straightdope.com/classics/a2_309.html-- Why do we yawn? http://faculty.washington.edu/chudler/yawning.html A yawn reasearcher? http://psychology.drexel.edu/ECNL/  Huh? Sorry must be groggy--Pictures of animals yawning --Oh No-- yawning out of control-- http://www.animalyawns.com/ all this reading about yawning ---YAWNS deeply--- I'm getting so sleepy ---  It's hard to keep my eyes open--z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z z
936410
because your brain thinks the other person is stealing all the air so makes you yawn to try and get some yourself, therefore staying alive.\n\nThere's also that it's merely the power of suggestion.\n\nFound this also http://in.answers.yahoo.com/question/index?qid=20061031003314AAoMMUh
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".
422922
It is also believed to be linked to social bonding.\n\nExperiments with chimps have shown that they also yawn when another chimp yawns.  Also videos (night video) in caves, where there is no light, where a certain species of monkey sleep - shows that they all yawn audibly before going to sleep.  Kind of a way of letting everyone know that they're there, even though they can't see each other.\n\nThis has probably carried through to humans.\n\nHave a look at http://www.theanswerbank.co.uk/Science/Question117042.html\n\nor\nhttp://webperso.easyconnect.fr/baillement/contagion-platek.html
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:
1178011
I know! why can't scientist study why yawns are so contagious?
775112
It's a sympathetic reaction that makes them contagious.  A yawn happens when your body is not receiving enough oxygen.  You yawn when someone else yawns because of this sympathetic reaction.  Mythbusters did an experiment on this topic on one of their shows.
687663
yawning is contagious because you watch the other person yawning.  However, over the phone it is not contagious.  Also, if you are sitting on the same room but do not see the other person yawning then it contagious.  It is a way of reciprocating unconsciously.
414199
Yawning, like laughter, can be infectious. As to why this should be, there is little hard evidence, although yawning may be an arousal response that arose early in evolution and whose aim is to improve oxygenation of brain tissue and increase alertness, with a view to enhanced survival. In social groupings, the sight of one member yawning might act as a signal to cause other members to yawn - in some way the yawn is a warning that attention is slipping and the group may be at risk…\n\nResearch into the physiology and pathology of yawning appears to be quite limited. However, I have come across a couple of useful references. The first gives a general description of what happens when we yawn:\n\n"Yawning is a response to a wide variety of stimuli, including sleepiness and an awakening from sleep, hunger, boredom, nervousness, and intracranial disease. It is infectious, occurs more frequently in the newborn, and is likely to be more vigorous (especially the accompanying stretch) in early morning than late at night."\n\n"A yawn consists of an expansion of the chest, descent of the diaphragm and larynx, elevation of the ala nasi and soft palate, downward and backward movement of the tongue, abduction of the vocal cords, wide opening of the mouth, contraction of the tensor veli palatini muscle, closing of the eyes, lacrimation, pulling the head backwards, stretching of the upper arms sideward and the lower arms upward, and, less frequently, stretching of the legs. Vasoconstriction in the digits and cardiac acceleration have also been found to accompany the yawn. The whole act occupies 5 to 10 seconds, most of which time is spent in the inspiratory phase."\n\n"Although yawning certainly is an effective way of fully expanding the lungs and increasing the venous return to the heart, its psychic implications are also of great interest. The author finds that merely writing this is a potent stimulus towards yawning, and perhaps the reader is similarly stimulated." (Fenn and Rahn 1964)\n\nA good review of yawning is provided by Askenasy (1989), and the points that follow are derived from this source. Apparently, yawning movements have been observed in fetuses as early as the 15th week after conception, and continue to occur sporadically throughout the remainder of pregnancy. The newborn baby yawns a few minutes after birth. The frequency of yawning gradually diminishes as the baby matures\n\n\nSeveral causes of yawning are discussed in the review:\n\n psychological - this includes boredom, drowsiness, fatigue, separation, imitation, and autosuggestion \n\n hormonal - ACTH and MSH \n\n neurological - various brain pathologies including coma, encephalitis, hypoxia, and neoplasms \n\n psychiatric - for example schizophrenia, psychosis, depression and withdrawal \n\n general pathologies - ear disorders, gastric and biliary disorders, and motion sickness \n\n drug overdose - for example naloxone, valproate, imipramine, clomipramine, seratonin, and pentobarbital \n\n drug withdrawal - from heroin, morphine, lefetamine, methadone, and pentazocin.
292528
Yawns usually occur because you have some lack of oxygen, usually when you are growing sleeping and not breathing properly. When a person yawms next to you, you usually stop breathing yourself, thus triggering a "contagious yawn." Need to prove this false? Next time you see someone yawn, be concious of it and make yourself take a deep breath. You wont get that contagious yawn!
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.
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
365189
The popular theory is that yawning is for oxygen boosting/carbon dioxine expulsion. Hwoever, this is contended, see http://en.wikipedia.org/wiki/Yawning for some other theories.\nThe fact that it is contagious is far more interesting though.\nThere were theories that it was related to the environment being the same, or even an exchange of chemicals. However, there is more debate now, as if you have a video conversation with someone on a webcam: same thing happens. You could be on different sides of the world, at different times of day, and you're still both yawning.\nAnother theory is that it's a subconscious psychological effect. You see someone yawning, and your subconscious thinks that it would rather like to do that, Interestingly, I have yawned quite a lot whilst I've been writing this, and I'm not tired at all.\nThere's a similar question to yours here http://www.straightdope.com/classics/a2_309.html\nBut the truth is, no-one really knows the answer.
829322
1- During a yawn, there is a slight increase in pressure inside the skull (likely caused by slight increases in the amount of oxygen taken in during a deep yawn). This causes the cerebrospinal fluid (CSF), the fluid that surrounds the brain and flows through the brain's ventricle system, to be forced out faster than normal. That fluid enters the lachrymal (tear) system. That increase in fluid pushes out the tears.\n\n2 - the more simplistic reason may be that when you yawn you scrunch up a bunch of facial muscles. That causes the tear glands and ducts to be squished, forcing out some tears.\n\n\nTalks about yawning as well:\nhttp://en.wikipedia.org/wiki/Yawn#Causes_of_yawning
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.