Why is yawning contagious?

Why is it that when we see people yawn, we get the urge to yawn as well? :)

This usually happens with me,whats the reason for this..

Have you ever notice,when you're in a room and you start yawning,loads of other people start yawning why is this?does everyon...

WHY?! I want to know why we do... its just a thing that I want to find out...

why do we yawn when other people yawn?

I thought since when we sleep, our airways expand a lot, so maybe it's ready to expand? Or doesn't it stretch your throat (i...

i got my yellow belly on friday and since then ive caught him yawning a couple of times. He seems really healthy but not sure...

I love to laugh, I laugh all the time. I laugh at people's jokes, I giggle when I talk to cute guys (well, guy), and just at ...

Whats the first thing(s) you do on the morning?? I usually feed my fish first along with my sis's cat and then unload my pee...

Hi there! Ok random is fun right??? Say yes or else =.=. Being hyper is fun right? You better say yes. Could these two be con...