I like this post by Lessig: Removing Blocks
There's a certain mindset out there that thinks the way the world was cut up in college is the way the world is. So whatever set of texts you read as a sophomore, somehow they define the nature of world forever. Seared in your brain is the excitement of figuring out the difference between Capitalism and Marxism, or communitarianism vs. libertarianism. And so significant was this moment of education that everything else in life must be ordered according to these sophomore frames.
I'm not even sure it's all that uncommon for thinking like this to solidify even before college. We learn that certain groups of people who are different from our preferred groups are "them." We start framing the world at a very young age. To put it another way, start building our "sophomoric frames" when we're just kids. Whether it's the kids at the other High School in town, or kids in the town next, maybe it's another ethnic group, or people who go to the other church in town. We learn how the world should be cut up, and we stick with it. It's probably the only way things can make sense.
It seems like framing also happens frequently when big changes disrupt life. Events like having kids, getting laid off, divorce, moving, or retirement seem to do something to a person that (from what I've seen) frequently causes an irrational shift in thinking that's hard to recover from. I suppose just getting older slowly hardens the mind as well. I suppose I could use the Pink Floyd analogy and say every day we put another brick in the wall.
It's really hard to stop and question one's beliefs, to really look hard at how you think about the world and ask if you're really being rational about things. From what I know of people, I think the answer is usually no, there's no time or energy for rational thought. There's only making it through today, and then dealing with tomorrow. Everything else can be learned from a sound bite or a rumor.