A comment about brain structure and brain plasticity to James G’s second instalment of Examining Idealism which I was unable to post over there (kept getting 404’s clicking “Post”):
That Kanazawa article is rubbish, because he does not control for educational status. Higher-IQ people will go to college more frequently, and we know who rules college. Even conservative-leaning students will learn to take the color of their environment. Now for the ACC and the rest. First, you say yourself that the main role of the ACC appears to be in dealing with conflicting information, and even that it helps people quickly respond to a frequently presented stimulus, but also withhold this response whenever a different stimulus occasionally appears. That sounds like a useful ability to have to practice crimestop and doublethink, ignore inconvenient facts etc. The authors of that Kanai study say as much, almost in plain words: individuals with a larger ACC have a higher capacity to tolerate uncertainty and conflicts, allowing them to accept more liberal views. So ACC cuts both ways, so to speak. Maybe it does enhance the capacity to exploit a novel environment, but it also enhances the capacity to believe in rubbish. Second, contrary to your belief, the brain is very plastic and modifies itself extensively in response to training, even in adults. Frequently-used areas will increase in size and unused ones will tend to shrink. For an example, look at the well-known studies of taxi drivers (here is a recent one).