I disagree, Hawk. People don't make up their beliefs, they are inculcated with them in childhood but it's not a voluntary process. You don't wake up and say, "I'm going to believe this today." You may change your beliefs over time but that's based on life experiences that forces the change otherwise you'll go on believing it. You never change beliefs on a whim. So you can't make them up. Your beliefs don't come from you, they come to you.

So I would say ALL people take on the typical beliefs of those around them--not just some. And this happens early in life and the people mainly responsible for that are parents. Kids take on the beliefs of their parents and most hold on to them for the rest of their lives unless forced by circumstances to reject them for something else.