Speaking at the Public Choice Outreach seminar this afternoon, Robin Hanson repeated an hypothesis he's been entertaining for a while: Liberals are trying to show that they are caring; conservatives are trying to show that they are tough. Perhaps, but I'm skeptical.
For starters, when I looked at the connection between personality and partisanship, I basically found no relationship. I expected to see that on the Myers-Briggs Thinking/Feeling scale, Democrats would be more Feeling and Republicans would be more thinking. But they weren't.
Furthermore, when you look at how liberals and conservatives present themselves, it seems like both sides claim to be both caring and tough. Liberals proclaim themselves to be the "reality-based community." Conservatives write books like Treason and Godless saying that liberals are hateful people who like spitting in the face of their countrymen.
If I had to guess, I'd say that the main thing your left-right ideology says about you these days is just how traditional you are. When you find out that someone is conservative, you suspect that he is probably nationalistic, religious, etc.; when you find out that someone is liberal, you suspect that he is cosmopolitan and secular. Relatively speaking in both cases, of course.
Admittedly, though, my personal contact with both liberals and conservatives is very limited. So tell me: When you find out that someone is a liberal or a conservative, what do you infer? Inquiring minds want to know...