I've written a lot about the difference between conservatism and liberalism. I'm familiar with Haidt's thesis about the difference in values, and with the concept of an authoritarian personality. It's fashionable to look at brain studies to account for cultural differences. But would the difference in brain activity be a cause or an effect here? Of course, liberals and conservatives might end up thinking differently, which would rewire their brains into different thought patterns. But that might be the effect of more complicated differences. If there were neural or genetic differences even in children who go on to divide themselves into liberals and conservatives, that would be intriguing. The concept of the authoritarian personality, too, is controversial.