Why as we get older we go from more liberal to more conservative.

As I have gotten older, I view myself as more conservative. Right now I can't even describe why I believe this is so; I just feel that I have. I'm wondering why I have changed? What generated the change? What I'm beginning to believe is that my belief that people can change and are good, has dimmed. My self absorbtion has increased; and as it has increased, my empathy for the pain and suffering of others has decreased. This thought is unfinished and only for myself, but I find it some how liberating that someone else may read my half formed though.