"Do we learn the most from people whose views we share."
Who are they! from whom we learn the most. Are they one who belong to faction in which we ourselves belong or one who actually are there to contradict the views of our camp. While answering this question I think, we already have people supporting our views. In general they would provide supporting facts to our views. But when we talk about learning we need people who actually oppose our ideas.
In general if we think of a day to day task like smoking a cigarette. I might feel, that life is about enjoying and looking dude, and that can be achieved if I am a smoker. I already have a friend who sits with me and smoke and also tell me facts which matches to that of mine. So here we see, I definately needed a friend who can tell me the cons of smoking, who can explain me the meaning of the so called "STATUTORY WARNING", which I may not be aware of or I have ignored.
Having a counterattacking group always help in broadening the spectrum of our studies. When discovered the speed of sound, one would have concluded that speed of sound is 780m/sec, ending up with some miscalculations in tracking vessels from submarine, until someone would have actually given a statement, "no its not always the same, it depends on the medium". We would have probably broaden our study area not just to air and water now but in other medium as well, either to prove other person's statement wrong or justify it.
The above facts seemed to practical. But as we talk of our moral values, we might strengthen ours, learning it from people of our group. But again we might have missed some values to ponder over, which actually can be learnt from others who follow them. As a human, we can very well derive from the facts what is morally correct and what is wrong only if we know the end result, we know the consequences, we know the supporting fact. All this can be acquired from one who differs in the way we think.
We generally prefer to live a life which is not monotonous. Had we have learnt from the people sharing the same view, we would have never tried something different, something adventerous. We would have never voted for vents. We would have followed trivial rules and regulations. But the diversities we see in everyday life, the competition we see, the various kinds of ventures actually gives the feeling, we do learn from the people we share our views but we learn the most from them who actually opposes them.