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BS: Why is yawning so contagious?
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BS: Why is yawning so contagious? |
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Subject: BS: Why is yawning so contagious? From: JennieG Date: 25 Aug 06 - 03:47 AM Today at work a colleague yawned, then I yawned, then we both couldn't stop yawning......leading me to ponder: why is yawning so contagious? Cheers JennieG....yaaawwwwnnnnnnn....... |
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Subject: RE: BS: Why is yawning so contagious? From: Paul Burke Date: 25 Aug 06 - 03:50 AM Laughing is. Itching/ scratching. Going for a pee. Coughing, especially in a theatre or a church. All caused I believe by evil spirits entering the soul. |
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Subject: RE: BS: Why is yawning so contagious? From: skipy Date: 25 Aug 06 - 04:04 AM It may not be one of life's deepest mysteries, but as scientific conundrums go, it has a peculiar staying power. Why is yawning contagious? Fox Sea Lion Different animals, same yawn. (Credits: Road Safety Council of Western Australia, Massachusetts Division of Fisheries and Wildlife; NASA Goddard Space Flight Center) Click here for an online movie of a chimpanzee yawning in reaction to a video of another one yawning. (From Biology Letters, December 2004 online issue) -------------------------------------------------------------------------------- Researchers recently found that yawning isn't only catching among people; it is also among chimpanzees. (Click here for a brief video from this research.) No one has devised a fully convincing explanation of why. Compounding the mystery is the odd way in which the contagious power of yawning is largely unconscious. We can see someone yawn, yearn to replicate the action ourselves, and do it, all without thinking about it. Other times we're aware it is happening, though it still floats somewhere beneath the realm of reason and of purposeful actions. So what gives? In an effort to find the answer, the Finnish government recently funded a brain scanning study. The results turned up some hard-to-interpret, possible clues. It also confirmed the obvious: yawn contagion is largely unconscious. Wherever it might affect the brain, it bypasses the known brain circuitry for consciously analyzing and mimicking other people's actions. This circuitry is called the "mirror-neuron system," because it contains a special type of brain cells, or neurons, that become active both when their owner does something, and when he or she senses someone else doing the same thing. Mirror neurons typically become active when a person consciously imitates an action of someone else, a process associated with learning. But they seem to play no role in yawn contagiousness, the researchers in the new study found. The cells are have no extra activity during contagious yawning compared with during other non-contagious facial movements, they observed. Brain activity "associated with viewing another person yawn seems to circumvent the essential parts of the MNS [mirror neuron system], in line with the nature of contagious yawns as automatically released behavioural acts—rather than truly imitated motor patterns that would require detailed action understanding," wrote the researchers, with the Helsinki University of Technology and the Research Centre Jülich, Germany. The findings are published in the February issue of the research journal Neuroimage. But if seeing someone yawn doesn't activate these centers, what does it do to the brain? The researchers found that it appears to strongly activate at least one brain area, called the superior temporal sulcus. But this activation was unrelated to any desire to yawn in response, so it may be irrelevant to the contagion question, the researchers added. Possibly more significant, they wrote, was the apparent deactivation of a second brain area, called the left periamygdalar region. The more strongly a participant reported wanting to yawn in response to another person's yawn, the stronger was this deactivation. "This finding represents the first known neurophysiological signature of perceived yawn contagiousness," the researchers wrote. Exactly what the finding means is less clear, they acknowledged. The periamygdalar region is a zone that lies alongside the amygdala, an almond-shaped structure deep in the brain in the area of the side of the head. The periamygdalar region has been linked to the unconscious analysis of emotional expressions in faces. Why it would be deactivated in tandem with yawn contagion is unclear, the researchers said. One thing seems clear from the study is that "contagious yawning does not rely on brain mechanisms of action understanding," wrote one of the researchers, Riitta Hari of the Helsinki University of Technology, in a recent email. Rather, she continued, it seems to be an "'automatically' released (and most likely very archaic) motor pattern," or sequence of physical actions. In the study, volunteers looked at videos of actors yawning or making other mouth movements. Meanwhile their brains were scanned using functional Magnetic Resonance Imaging, a system that shows the amount of activity or work going on in various brain areas based on the amount of oxygen being used up there. The volunteers were later asked how strongly they had been tempted to yawn while viewing the pictures. Apart from the physical brain mechanisms of yawn contagiousness, researchers have offered different reasons as to why it exists. Some have proposed that in early humans, yawn contagiousness might have helped people communicate their alertness levels to each other, and thus coordinate their sleep schedules. This might be part of a more general phenomenon of unconscious signals that serve to synchronize group behavior, the authors of the Neuroimage paper wrote. "Such synchronization could be essential for species survival and works without action understanding, like when a flock of birds rises to the air as soon as the first bird does so—supposably as it notices a predator." Skipy |
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Subject: RE: BS: Why is yawning so contagious? From: Bagpuss Date: 25 Aug 06 - 04:14 AM Reading about yawning also makes you yawn... |
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Subject: RE: BS: Why is yawning so contagious? From: JennyO Date: 25 Aug 06 - 04:19 AM Just reading this thread is making me |
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Subject: RE: BS: Why is yawning so contagious? From: JennyO Date: 25 Aug 06 - 04:20 AM Heh! Great minds, Bagpuss.... |
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Subject: RE: BS: Why is yawning so contagious? From: Paul Burke Date: 25 Aug 06 - 04:22 AM Morphic resonance!!!! |
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Subject: RE: BS: Why is yawning so contagious? From: John MacKenzie Date: 25 Aug 06 - 05:37 AM There is only one yawn in the world, which passes from person to person, and you get it when it's your turn to have it! G. |
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Subject: RE: BS: Why is yawning so contagious? From: Becca72 Date: 25 Aug 06 - 08:25 AM It works with cats, too...my 3 will pass a yawn around all day long. |
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Subject: RE: BS: Why is yawning so contagious? From: GUEST,mack/misophist Date: 25 Aug 06 - 10:30 AM Some years ago the standard explanation was that excess levels of CO2 in the blood would trigger an automatic yawn in order to boost O2. I presume it's still true; which is not to say that other mechanisms can't apply also. |
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Subject: RE: BS: Why is yawning so contagious? From: Pied Piper Date: 25 Aug 06 - 10:39 AM A very thorough exposition skipy. PP |
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Subject: RE: BS: Why is yawning so contagious? From: Ebbie Date: 25 Aug 06 - 11:32 AM Ha, I say. Over and over again in this thread I felt the impulse to yawn. As an experiment I shifted my attention to something else. It's worked: so far I haven't yawned. I have a different question about yawning- Whenever I am chilly, especially outdoors, I yawn and yawn. Why? |
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Subject: RE: BS: Why is yawning so contagious? From: Little Hawk Date: 25 Aug 06 - 04:26 PM You probably need more oxygen, Ebbie. Oxygen is fuel, and burning it is what keeps your body warm. I feel like yawning all the time while reading this thread. Everything is contagious. People just notice it more when it's yawning for some reason. Y-a-a-a-a-a-a-a-a-a-a-w-w-w-w-n! |
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Subject: RE: BS: Why is yawning so contagious? From: Becca72 Date: 26 Aug 06 - 09:21 AM Found this on the 'net: Many people assume that we yawn because our bodies are trying to get rid of extra carbon dioxide and to take in more oxygen. This may make some sense. According to this theory, when people are bored or tired, they breathe more slowly. As breathing slows down, less oxygen makes it to the lungs. As carbon dioxide builds up in the blood, a message to the brain results in signals back to the lungs saying, "Take a deep breath," and a yawn is produced. The only problem with the excess carbon dioxide theory is that research shows that it may not be true. In 1987, Dr. Robert Provine and his coworkers set up an experiment to test the theory that high carbon dioxide/low oxygen blood content causes yawning. Air is normally made up of 20.95% oxygen, 79.02% nitrogen), 0.03% carbon dioxide and a few other gases in low concentrations. The researchers gave college students the following gases to breathe for 30 minutes: Gas #1 = 100% Oxygen Gas #2 = 3% Carbon dioxide, 21% Oxygen Gas #3 = 5% Carbon dioxide, 21% Oxygen Gas #4 = Normal Air Breathing 100% oxygen (Gas #1) or either carbon dioxide gas (Gas #2 and #3) did cause the students to breathe at a faster rate. However, neither carbon dixoide gas nor 100% oxygen caused the students to yawn more. These gases also did not change the duration of yawns when they occurred. The researchers also looked for a relationship between breathing and yawning by having people exercise. Exercise, obviously, causes people to breathe faster. However, the number of yawns during exercise was not different from the number of yawns before or after exercise. Therefore, it appears that yawning is not due to CO2/O2 levels in the blood and that yawning and breathing are controlled by different mechanisms. So, the question remains - why do we yawn? Dr. Provine suggests that perhaps yawning is like stretching. Yawning and stretching increase blood pressure and heart rate and also flex muscles and joints. Evidence that yawning and stretching may be related comes from the observation that if you try to stifle or prevent a yawn by clenching your jaws shut, the yawn is somewhat "unsatisfying." For some reason, the stretching of jaw and face muscles is necessary for a good yawn. |
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Subject: RE: BS: Why is yawning so contagious? From: JennyO Date: 26 Aug 06 - 01:37 PM I yawn when I'm bored, more than when I'm tired. I'm not bored reading this thread though. I'm finding it very interesting. So why am I yawning? Just the mere thought of yawning makes me yawn - and I often stretch when I yawn. A good stretch is very satisfying. I always try to remember to have a good stretch just as I'm getting up. It seems to get me going for the day. I think Dr Provine might be onto something! |
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Subject: RE: BS: Why is yawning so contagious? From: Little Hawk Date: 26 Aug 06 - 01:46 PM Stretching is good for the body, so it probably has a lot to do with that, allright. |
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Subject: RE: BS: Why is yawning so contagious? From: McGrath of Harlow Date: 26 Aug 06 - 05:16 PM It's contagious with other primates as well. Just try yawning next time you're in the zoo in front of a bunch of apes or monkeys and see. I think it's probably some kind of group bonding thing. |
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Subject: RE: BS: Why is yawning so contagious? From: The Fooles Troupe Date: 26 Aug 06 - 09:01 PM "probably some kind of group bonding thing." Like smiling - a non-threat signal? |
