Why are yawns contagious?

Answer 1

Pandiculation is the act of stretching and yawning
-Everyone yawns - babies, kids, teenagers, adults.
-Some birds, reptiles and most mammals also yawn.

Here are a few things that are known about yawns:
1.The average duration of a yawn is about 6 seconds.
2.In humans, the earliest occurrence of a yawn happens at about 11 weeks after conception - that's BEFORE the baby is born!
3.Yawns become contagious to people between the first and second years of life.
4.A part of the brain that plays an important role in yawning is the hypothalamus (Part of the forebrain that regulates the amount of fear, thirst, sexual drive and aggression we feel).
-Research has shown that some neurotransmitters (for example, dopamine, excitatory amino acids, nitric oxide) and neuropeptides increase yawning if injected in the hypothalamus of animals

But WHY do we yawn?
-You know that when we are bored, we 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

But WHY do we yawn when we’re bored?
-Many people assume that we yawn because our bodies are trying to get rid of extra carbon dioxide (CO2) and to take in more oxygen (O2).
-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 CO2 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 CO2/low O2 blood content causes yawning.
-Air is normally made up of 20.95% O2, 79.02% N2 (nitrogen), 0.03% CO2 (and a few other gases in low concentrations).
-The researchers gave college students the following gases to breathe for 30 minutes:
Gas #1 100% O2
Gas #2 3% CO2, 21% O2
Gas #3 5% CO2, 21% O2
Gas #4 Normal Air
-Breathing 100% O2 (Gas #1) or either CO2 gas (Gas #2 and #3) did cause the students to breathe at a faster rate.
-However, neither CO2 gas nor 100% O2 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.

Answer 2

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. Studies partially explain the reason for yawning. Although we yawn more when sleepy or bored, it is unclear whether yawning increases alertness. And scientific evidence refutes one of the most popular myths of yawning— that it happens in response to low oxygen or high carbon dioxide levels in the blood or brain. Test subjects do not yawn more when breathing air with enhanced levels of carbon dioxide nor do they yawn less when breathing pure oxygen. One fact explains a lot of apparently inconsistent data. People yawn most during behavioral transitions, such as just after waking and shortly before bedtime. Yawning may help facilitate those changes. Contagious yawning may synchronize a group's behavior so that, for instance, a whole family goes to sleep together.

Answer 3

Good question. I am interested in seeing what type of answers you get.

From what I have heard, yawns are contagious because the body automatically/subconsciously recognizes the other person yawning and the benefits that come with it (more oxygen, etc.) and then in turn makes the viewer yawn too. Yawning breaks the normal short breath pattern and provides more oxygen to the brain.

Answer 4

When you yawn, it changes the air pressure in your ears. It also changes the air pressure for anyone near you, thus making a yawn contagious. *yawn* ; )

Answer 5

the reason we yawn is with the help of the fact our respiration slows inflicting a loss of oxygen and so we yawn to take up a deep breath, it particularly is why we yawn as quickly as we are drained-our respiration slows down. And as quickly as we see somebody else yawn our respiration slows down slightly returned so we yawn :)

Answer 6

lol you just made me yawn

Answer 7

They just make everyone else sleepy

Answer 8

*yawnZ*... indeed contagious...

Answer 9

may be it is visual