A Gentleman told me he read that we yawn to cool our brain. Has anyone else heard of it?

I was taught in my biology lesson that morning that yawning provides oxygen to the brain, and helps us stay alert whilst awake. Later that afternoon, whilst in a physics class, I couldn't stop yawning. The teacher asked me to stop - thinking I was doing it on purpose. I replied that I was just letting my brain breath. She thoughtI was answering back, and sent me outside for the rest of the lesson!

i read just that on yahoo a while back. well if i remember correctly an example is like after we study for a while we yawn and get tired, so supposedly we yawn to cool our brains from all that thinking or something..

i heard that when we yawn its for oxygen

that our brain needs it..

dont know tho

:D

i yawn when im bored or sleepy... our brain doesnt need cooling cuz our peripheral system already does that for us..

Well i don't know.....