Hardwired ideology

I was talking to a friend today about what seems to be a widening gap in political ideology. She was wondering if, given the huge differences between political blocks, the differences might be structural. Put another way, that these difference might be hardwired into people's brains. I think that's the only way she could personally reconcile the commonality of polar opposition in basic attitudes.

I didn't think too much of the idea at the time, since I believe that most social attitudes are the result of acculturation, but after reading the morning news and watching a few Republican attack ads, I thought: what about brain damage?