why do we yawn when we see any one yawning?

Answer 1

It is a matter of pressure. A person yawns to equalize the pressure in their head. This changes the pressure in the room. This causes everyone else in the room to yawn to equalize their pressure.

It is a never ending cycle.

Answer 2

Yawning is the primary sign and symptom of a very short lived infection known caused by the Mandibulus Stretchoutii virus.

It is transmitted via airobrne droplets created by a carrier yawning, so anyone in the immediate vicinity is almost certain to be exposed.

The incubation period is approximately 0.05 seconds, and the diesease is easily fought off by the bodies immune defenses in less than 5 seconds, resulting in a yawn or two per infection at most.

The disease can only survive a short time inside a human host, but it can easily be passed back and forth between people in close proximity, and it can suvive in room temperature air almost indefinitely inside a dried viral spore droplet - which is why some people also yawn without a previous yawn in the area spreading fresh spores.

There is no known vaccination or cure for M. stretchoutii infection, but since the diease is self limiting and of such mild, short course, it is generally overlooked by the medical community at large as insignificant.

Answer 3

Everyone yawns - babies, kids, teenagers, adults. Some birds, reptiles and most mammals also yawn. However, the reason why we yawn is a bit of a mystery. There is also very little research about yawning because for most people yawning is not a problem. Here are a few things that are known about yawns:

The average duration of a yawn is about 6 seconds.
In humans, the earliest occurrence of a yawn happens at about 11 weeks after conception - that's BEFORE the baby is born!
Yawns become contagious to people between the first and second years of life.
A part of the brain that plays an important role in yawning is the hypothalamus. Research has shown that some neurotransmitters (for example, dopamine, excitatory amino acids, nitric oxide) and neuropeptides increase yawning if injected into the hypothalamus of animals.

You know that when you are bored, you yawn. Scientists have confirmed this observation by comparing the number of yawns in 17-19 year old students who watched music videos to the number of yawns in students who watched an uninteresting color test bar pattern.

As you might have expected, people who watched the color test bar pattern yawned more (5.78 yawns in 30 minutes) than those who watched the "MTV-like" video (3.41 yawns in 30 minutes.) The average duration of yawns was also slightly longer in the test bar viewing group. One unexpected finding was that yawns in male students had a longer duration than those in female students.


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.

It is possible that yawns are contagious because at one time in evolutionary history, the yawn served to coordinate the social behavior of a group of animals. When one member of the group yawned to signal an event, all the other members of the group also yawned. Yawns may still be contagious these days because of a leftover response (a "vestigial" response) that is not used anymore. None of this has been proven true and yawns are still one of the mysteries of the mind.

Answer 4

yawning is contagious.

evolved to coordinate the behavior of a group of animals.
It's more efficient for a nomadic group if most sleep at the same time.

Whatever written by CSlave is real bullshit,.. excuse my language

Answer 5

if u yawn when others yawn...then taht means u r very intelligent.....it is based on how much time u take after the other person yawn.....if the gap is long then u r less intelligent ....gap of yawning is less then u r intelligent...scientifically prooved.

Answer 6

i have no idea but i yawned when i read the word

Answer 7

yaar dis same qtion is troubling me also...u yawn not only wen u see yawing but also yawn u hear someone yawing over headphones...i think itz based on our mentality...

Answer 8

Our reactions don't like to be different from others (even though they are)... i raeally don't know. that is the best answer i could think of. i'll keep note of this question...

Answer 9

may be u have gone mad.i have never observed such things.

Answer 10

it reminds others that it is the time to sleep.