Why do people rural areas tend to be more conservative, and those in cities more liberal?

I've wondered about this for a long time. For a while I figured that those living in cities tend to be more educated, and that more education allowed you to see the truth more clearly, and the truth was that liberal was better. Since I'm a liberal, this fit in nicely with the way I viewed the world.

However, I was never completely satisfied with this. "Uneducated" people may not have had a lot of formal education, but that doesn't mean they haven't learned anything, just that they got their learning through real-life experiences rather than in a class room. Also, there are a lot of uneducated people in the cities, and yet they still tend to be liberal.

This morning, I came up with a different theory. The idea is that we have a natural tendency to establish a certain level of social pressure in our societies. Where there are more people, the amount of social pressure that each person expresses has to be less in order to maintain this level, and where there are fewer people, each person has to express more social pressure.

To put it another way, when there are strangers all around you, you always feel a certain pressure to behave properly, and the last thing you want is more rules telling you how to behave. If you live in an area people live farther apart, there's a lot more opportunity to just do what you want, and people naturally feel a lot more responsibility to keep the people around them in line.

Of course, as I write this, I'm thinking of a lot of other possibilities as well. In the country, people tend to all know each other, whereas in the cities, there is a lot more anonymity. You often hear people who move from the country to the city saying that in the country, you can't do anything without some neighbor finding out about it and telling your parents. (Okay, I guess I heard this back in college from people who'd come from rural areas, but I think it applies to all age groups.) It may be that people who prefer more social freedom move to the cities, so it may be that the cities attract more liberal people rather than the cities make them liberal.

Another related factor may be that people feel the most pressure to conform during their teen years, after which, they've internalized the rules of their own society. It may be in the country, where everyone knows each other, and more importantly, know your parents, there is a lot more pressure to conform. If you stick it out, rather than moving to a large city, you adopt the rules of your society as your own.

It may also be that, in a rural society where everyone knows each other, there's really only room for one set of social rules. As you grow up there, you're only exposed to one set of rules, so you naturally assume that those are the right rules and everyone else should have those rules as well. In the city, there are a lot more people, and they tend to form sub-cultures, so people who live in the city can witness a lot of different ways of thinking first-hand.

And we shouldn't rule out the "education" effect either. The ideas that we learn through a formal education tend to come from people who've written books. Social ideas come from people who've written books about society, and these tend to be people who've done a lot of thinking about society. People think about the challenges they face, so the people who think a lot about society may tend to be those who don't fit well in their own society, and who wish their society was a little different, or at least a little more forgiving of their eccentricities, i.e. liberals.

There are probably a lot of factors that feed into this difference between rural and urban areas, some of which may be opposing, but the end result is as obvious as looking at a red/blue political map during an election. Rural states, and rural counties within states, are almost always red, and urban states and counties are almost always blue.