When you hear someone talk about yawning, or see someone else yawn, it tends to make you yawn as well, which makes me believe there's something psychological about the cause.
Anyways, sometimes when I'm tired my contact lenses get dry and itchy, and I try to make myself yawn to wet my eyes (since, as mentioned before, yawning tends to "make you cry", so it is kind of useful to me on occasion.
Also, I yawned three times while writing this message.
Yawning sends oxygen and extra blood to the brain. During yawning, intellectual activity stops and we cannot think for a moment. We usually start yawning when we are very tired, before sleep, when we are too excited, or extremely serious.
Yawning sends oxygen and extra blood to the brain.
As mentioned before, this is just a theory and there is no proven answer to why we yawn.
During yawning, intellectual activity stops and we cannot think for a moment.
That's just silly, I can definitely think while yawning.
when we are too excited, or extremely serious.
I find this kind of silly too. You yawn when you're tired, bored, or sometimes when you see others yawn. What I just quoted sounds like the excuse a really lazy student would give for yawning during class (I should know, being really lazy myself).
As mentioned before, this is just a theory and there is no proven answer to why we yawn.
A person yawns because their brain sends a message to the body that it needs more oxygen. So basically, our lungs expand fully with oxygen and it also helps remove any build-up of carbon dioxide. Seems pretty close to proof to me...
I find this kind of silly too. You yawn when you're tired, bored, or sometimes when you see others yawn.
You just stated half of what I just said. As for the "extremely serious", that was a typo, I meant "extremely nervous", which happens to me all the time because I have stage fright anxiety attacks. To answer why you yawn when others do, normally you are in close proximity to other people--and therefore are removing more oxygen from them and this triggers others to yawn. This happens quite a bit during meetings or in classrooms, or if you are stuck in a conference room--the same concept occurs, where there might be limited air movement in the room and one person yawns and inhales large quantities of oxygen. So everyone else yawns because their brain gives the signal that there is less oxygen in the air and the body reacts accordingly and yawns.
You guys realize that this is an '09 thread, right!?
You realize you're spamming right now, right?!
And so am I right now, kind of.
Anyways, mostly just to make my post more relevant and not purely spammy, according to Wikipedia, some animals yawn to threaten their enemies or show dominance.
A person yawns because their brain sends a message to the body that it needs more oxygen. So basically, our lungs expand fully with oxygen and it also helps remove any build-up of carbon dioxide. Seems pretty close to proof to me...
I see your lack of evidence and counter with a Wikipedia quote:
One states that yawning occurs when one's blood contains increased amounts of carbon dioxide and therefore becomes in need of the influx of oxygen (or expulsion of carbon dioxide) that a yawn can provide,[4] but studies have since shown it to be either incorrect or, at the very best, flawed.[6] Yawning may in fact reduce oxygen intake compared to normal respiration, not increase it.[7]
The physiological theory: Our bodies induce yawning to draw in more oxygen or remove a buildup of carbon dioxide. This theory helps explain why we yawn in groups. Larger groups produce more carbon dioxide, which means our bodies would act to draw in more oxygen and get rid of the excess carbon dioxide. However, if our bodies make us yawn to draw in needed oxygen, wouldn't we yawn during exercise? Robert Provine, a developmental neuroscientist at the University of Maryland, Baltimore County and a leading expert on yawning, has tested this theory: 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 [source: University of Washington].
See, there's another source in there for you too. And I even boldified (yes that's a word now) the important part.
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 [source: University of Washington].
I never said this. I said that a decrease in oxygen or increase in carbon dioxide causes a yawn. What you marked in bold was the opposite.
No. The test results showed that people who received additional oxygen did not yawn less. If they received more oxygen and yawned as much as those who didn't, then they did not yawn because of a lack of oxygen.
The test also showed that people who received less carbon dioxide did not yawn less either, so yawning was probably not caused by having an increase in carbon dioxide.
I said that a decrease in oxygen or increase in carbon dioxide causes a yawn.
