On the whole, the research shows, conservatives desire security, predictability and authority more than liberals do, and liberals are more comfortable with novelty, nuance and complexity. If you had put Buckley and Vidal in a magnetic resonance imaging machine and presented them with identical images, you would likely have seen differences in their brain…The volume of gray matter, or neural cell bodies, making up the anterior cingulate cortex, an area that helps detect errors and resolve conflicts, tends to be larger in liberals. And the amygdala, which is important for regulating emotions and evaluating threats, is larger in conservatives.
While these findings are remarkably consistent, they are probabilities, not certainties—meaning there is plenty of individual variability… There is also an unresolved chicken-and-egg problem: Do brains start out processing the world differently or do they become increasingly different as our politics evolve?
Partisanship does not just affect our vote; it influences our memory, reasoning and even our perception of truth. Knowing this will not magically bring us all together, but researchers hope that continuing to understand the way partisanship influences our brain might at least allow us to counter its worst effects: the divisiveness that can tear apart the shared values required to retain a sense of national unity.