I'm reading Chris Mooney's latest, The Republican Brain, which attempts to explain the differences between conservatives and liberals based on their psychological makeups. For instance, conservatism correlates negatively with openness but positively with conscientiousness. He also talks about episetemic closure, which psychology predicts (and we can observe) is far more likely on the right than on the left.
I plowed half-way through the book yesterday, and I expect to finish it on the plane Wednesday. As Jon Stewart would say, buy it, read it, it's on shelves now.