Named for the Greek word for almond because of its analogous size and shape, the amygdala is located at the base of the brain deep within the temporal lobe. A previously obscure and little studied structure, the amygdala has more recently taken center stage in the neuroscience arena. It appears to function as a way station that links multiple sensory inputs to a variety of destinations critical to the formation of emotion linked memory. As a consequence of this arrangement, sensory information is frequently reshaped to fit within an emotional response constructed from previous amygdala generated experience. You don't read Paul Krugman or Joe Romm, and I don't listen to any of a variety of conservative icons, without a predictable series of amygdala driven responses.
The point I was trying to make with Ideological Voter was that none of us (at least not this middle aged man co-writing a blog) come to politics without a set of preconditioned notions about the way we want the world to be. Those notions are the product of our life's experience, temperament etc, but the degree to which they are predetermined is likely much greater than we would care to admit. There is precious little chance that I, the Jewish grandson of New York socialists, schooled at a bastion of Eastern liberalism, and comfortably ensconced in an academic career, was going to look at politics much differently than I do. I would wager the same predictability applies to most of us.
So just set those primitive responses aside, you might argue, and act rationally That's more easily said than done alas. Evolutionarily speaking, the amygdala is a very old structure designed to perform an essential function, which is to make us so scared sh-tless by a perceived threat that we will instantly react in whatever way we need to save ourselves. The fallout comes of course when the perception of threat falls to match the reality.