I'm convinced that economists have a lot to learn from personality psychology. For example, personality is a great predictor of occupational choice. Librarians are highly introverted, and salesmen are highly extraverted, just as you'd expect. Preferences matter, Becker and Stigler notwithstanding.
It's not too surprising, then, that I once strongly suspected that personality differences would be an important predictor of political differences. At least in the literature I've searched (a lot) and the data sets I've looked at (two), however, there is very little evidence of a connection.
But today some evidence landed on my desk that cuts the other way. A recent German study reports some intuitively plausible links between personality and political orientation. Here is how author Siegfried Schumann responds to the question "What kind of personality traits are most relevant?":
There's two: A readiness to experience new things -- having various interests, being imaginative, profound and visionary -- and conscientiousness concerning planning, organizing and conducting tasks. Two parties are at the opposite end of the spectrum: Supporters of the Greens are by and large open for new things and not very conscientious. On the other side are those voting for the Christian Democrats: They are very conscientious and lack openness to new experiences.
If you are more familiar with the semi-popular Myers-Briggs (or "Jungian") model rather than the more academic Five Factor Model, Schumann's results basically say that:
1. Greens are more N ("intuitive"), Christian Democrats are more S ("sensing")
2. Greens are more P ("perceiving"), CDs are more J ("judging")
All this leaves me wondering: Is German politics more about personality type than U.S. politics? Or are the effects just small enough that they're easy to miss?