What causes yawn?

Answer 1

The body needing an intake of air. Also, it is the body's way of stretching the facial muscles. Plus, it lubricated the eyes.

Did you know that you can only pass a yawn on to a friend?! Try it to test ya friends, teehee

Answer 2

While the dictionary tells us that yawning is caused by being fatigued, drowsy or bored, scientists are discovering that there is more to yawning than what most people think. Not much is known about why we yawn or if it serves any useful function, and very little research has been done on the subject. However, there are several theories about why we yawn. Here are the three most common theories:


The Physiological Theory --
Our bodies induce yawning to drawn in more oxygen or remove a build-up 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 drawn in needed oxygen, wouldn't we yawn during exercise? Robert Provine, a psychologist 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.

The Evolution Theory --
Some think that yawning is something that began with our ancestors, who used yawning to show their teeth and intimidate others. An offshoot of this theory is the idea that yawning developed from early man as a signal for us to change activities. Even babies in the womb yawn.

The Boredom Theory --
In the dictionary, yawning is said to be caused by boredom, fatigue or drowsiness. Although we do tend to yawn when bored or tired, this theory doesn't explain why Olympic athletes yawn right before they compete in their event. It's doubtful that they are bored with the world watching them.

The simple truth is that even though humans have been yawning for possibly as long as they have existed, we have no clue as to why we do it. Maybe it serves some healthful purpose. It does cause us to draw in more air and our hearts to race faster than normal, but so does exercise.

There's still much we don't understand about our own brains, so maybe yawning is triggered by some area of the brain we have yet to discover. We do know that yawning is not limited to man. Cats, dogs, even fish yawn, which leads us back to the idea that yawning is some form of communication.

Have I provoked a yawn out of you yet? If I have, hopefully it's not out of boredom, but by the power of suggestion.

Next time you're in a meeting or a group, try this little experiment: Take a big yawn, cover your mouth out of courtesy, and watch and see how many people yawn. There's a good chance that you'll set off a chain reaction of yawns.

Answer 3

In fact this is a very, VERY good question.
In reality the reason is multi-faceted for the following reasons.
If the level of carbon dioxide has risen in a room say at then end of a long day in class and its warm to the body will generate a yawn to take in extra oxygen and also to remove more carbon dioxide from the system.
Also the yawn creates a stretch which then brings carbohydrate from storage areas like fat cells and also muscle into play thus you feel more exhilarated after the yawn.
In effect the body is caused to stir from imminent sleep.
We also do the same often first thing in the morning to gain a little energy boost before we consume our breakfast and directly after we wake up.
It is indeed autosuggestion that causes others to yawn but this is again a predisposition and pre-programmed into our system as this is a subconscious sign that there are falling levels of Oxygen and rising levels of Carbon Dioxide in the room.
You don’t often see people yawn outside or in very large open areas like for example football stadiums.
Interestingly when one sneezes one is closest to death without dying all body function, heart rates, breathing etc ceases for the micro second that you sneeze, and you will no doubt know that you can not urinate when you sneeze you stop whilst you are sneezing and then start again as soon as the sneeze is complete this is because the sphincters controlling the bladder close for he micro-second that the sneeze lasts.
See ya
Paul

Answer 4

No one really knows, that's not to say that research hasn't been going into it. Yawning is a very common things in Animals on Earth. Birds, Cats, Fish and new borns all yawn constantly.

One theory claimed you yawned if you had too little oxygen in your blood. But you yawn even if you are breathing 100% pure oxygen. Sometimes you yawn if you are tired, but highly-alert athletes often yawn just before a big event. Soldiers will often yawn just before an exercise.

During tests into the subject (strangely enough the test was on Siamese Fighting Fish) they discovered something else interesting. The fish yawned up to 5 times more often in the company of other fish, so the current idea is that it is something to do with a social setting. I bet at least 50% of the people that even glanced at this topic yawned.

Odd isn't it

Answer 5

I agree with "soldevi" a yawn isn't for an increased oxygen intake at all,because when you yawn you don't take in much if any more oxygen than taking a normal deep breath.
A lot of researchers into this have agreed that they haven't got very far finding out exactly why we yawn so it's a good question,well worth a star.

Answer 6

Lack of oxygen in the body. As you drift towards sleep your breathing becomes shallow and you may not be taking in enough air. Yawning overcomes this. What I don't understand is why if one person in a room yawns, most other people in the room will also yawn.

Answer 7

Yawning is caused by lack of oxygen to the brain

Answer 8

Lack of oxygen in the brain cause you to yawn, especially when tired.

Answer 9

A need for immediate intake of air into your body, especially when you are tired. Your lungs require extra oxygen and a message is sent to your brain to yawn.

Auto suggestion when somebody else yawns!

Answer 10

a yawn is caused when there is not enough oxygen in your lungs its nothing to do with being tired its just a natural reation to brathing in more air.