Yawning

[nerd1]

up to now there has been no viable, widely accepted explanation for the Yawn.
there still isn't.
However, I recently had a theory about this.
here it is:
I think yawning is a defense mechanism.
my argument for this is:

when you yawn you expose your teeth.[/li]I believe that this developed as an unconscious reflex for tired animals. By periodically showing their teeth when tired they kept other animals wary, so they were less likely to attack while they were tired.[/li]yawns are contagious- if you yawn you may very well cause someone else to yawn, and vica-versa. this would be another unconscious defense mechanism, when frightened animals show their teeth, so animals developed the counter yawn as another unconscious reflex- when someone threatens you- shows their teeth- you show yours right back.[/li]

what do you think? I do not have any proof of this; for now it is merely speculation.

[Demagog]

Actually, yawning changes the pressure inside your ears. This changes the pressure outside your ears, which means other people will need to alter the pressure inside their own ears to match the new pressure outside their ears. That's why yawning is contagious.

[Xenocidius]

Regarding yawns being contagious - I think the question you're asking here is: yawn chain - how?

[willng3]

I yawn every single time a person in chat says *yawn*.  I'm sure there's a scientific explanation for that.

[YawnChainHow]

Your brain is one big huzzbuzzdebeedlydoobop of information. Cells in your brain are always busy communicating, and they do this by sending electric signals along pathways known as neurons. These cells also send and receive signals to and from your body. THEY ARE YOU.

Anyways, there's this one type of neuron known as a mirror neuron.

THE GAME

You just thought of The Game. Now SHOUT IT LIKE YOU MEAN IT

In reality, this is pretty much how yawns are chained. The neurons that tell your brain you just saw someone yawn are the exact same neurons that tell your body to make you yawn. Hence why they are known as mirror neurons. One causes the other because their signals are sent along the same pathway.
This can also be extended to apply to making eye contact and vomiting. Maybe. The Game.

Also we can see that willng3 is an evolved form of human whose neuron for reading about yawning is a mirror neuron!

[Rutarete]

I like your theory, Nerd.