In my dim recollection of school, I was one of the people who sat at the back of the class and I only tried to communicate with the person directly in front of me. The one exception was Physics, but that was because Mr. Harp was awesome. He looked precisely like every man in every Herman comic strip and was easily a billion times funnier. I wanted to sit close enough to hear everything he mumbled.
Anyways, there were times that I knew the answer to the question the teacher was asking ("Anyone? Bueller?"), but I almost never spoke up. I never really understood why teachers would ask the students. Weren't we supposed to be learning from them? Surely they knew the answer. And they were getting paid to make sure that knowledge was passed on to us. Waiting for some smarty-pants to blurt something out - right or wrong - was a waste of time. And I don't recall that it achieved any kind of class unity or even competition. Did the less knowledgeable students want to become more like the brown-nosers? I doubt it. And it certainly didn't make the ones with the answers more popular.