it spreads without warning, it can pass through glass or just by sound alone!

hardly anyone is Immune, and you`ve probably been affected MANY times in your life by it!

 

YAWNING...

 

 

WHY, is that when someone yawns, 9 times out of 10 you`ll yawn as well?

 

what mechanism is at play here and what social role?

I've seen a few things on why yawning is contagious. The truth is nobody really knows why. A common theory is that it is a learned response. I don't believe in that one, seems a little odd that both we and chimpazees would learn that. Another is that it is that it is actually evolutionary. That, at one time our ancestors used yawns to signal each other, and the others followed that yawn with their own.

I thought I read somewhere that yawning was a response to inadequate amounts of oxygen and/or balancing our levels of CO2. If this were the case, we would take our cue from others in the room. One person yawns signaling the lack of oxygen, you'd likely follow..

how does that apply to tiredness though?

 

I agree that a lack of O2 is a key player in the initiation of some yawns, but folks can, and do yawn outside, and it`s still as contagios

Actually I've heard that they no longer believe that is true. Now they say yawning seems to be more a response to boredom or tiredness. There have been studies where people watching something interesting yawn less than people who get to watch the little off-air bars. I think the study was teens watching MTV videos versus those bars. Depending on the video, I might opt for the bars...

I found this:

http://faculty.washington.edu/chudler/yawning.html

 

It's a bit of a help.

http://en.wikipedia.org/wiki/Yawn

I just yawned after reading this thread. So it’s at least a little psychological.

perhaps I should have added "in TEXT" too

even people that can't control it, can shoot their salivary glands when they yawn. it is pretty cool, but it is off topic. i have developed it to where i can do it any time i want and i can get it to go about 4 or 5 feet.