Social Groups rather than Facts Shape our Opinions

Our attitudes are shaped much more by our social groups than they are by facts on the ground. We are not great reasoners. Most people don't like to think at all, or like to think as little as possible. And by most, I mean roughly 70 percent of the population. Even the rest seem to devote a lot of their resources to justifying beliefs that they want to hold, as opposed to forming credible beliefs based only on fact. 

Think about if you were to utter a fact that contradicted the opinions of the majority of those in your social group. You pay a price for that. 

I live in a very limited universe, and so I have to depend on the beliefs and knowledge of other people. I know what I’ve read; I know what I’ve heard from experts. In that sense, the decisions we make, the attitudes we form, the judgments we make, depend very much on what other people are thinking. 

Steven Sloman quoted in Vox

Using Peer Pressure to our advantage

In a 1994 Harvard study that examined people who had radically changed their lives, for instance, researchers found that some people had remade their habits after a personal tragedy, such as a divorce or a life-threatening illness. Others changed after they saw a friend go through something awful... Just as frequently, however, there was no tragedy that preceded people's transformations. Rather, they changed because they were embedded in social groups that made change easier… When people join groups where change seems possible, the potential for that change to occur becomes more real.

Charles Duhigg, The Power of Habit: Why We Do What We Do in Life and Business