People with conservative views have a larger amygdala, a primitive part of the brain associated with fear, new research shows.
People with more liberal views, on the other hand, have a bigger anterior cingulated cortex, a region of the brain linked to decision-making.
Research led by Wellcome Trust senior research fellow Professor Geraint Rees uncovered the differences by giving magnetic resonance imaging (MRI) scans to ninety young adults who had reported their political attitudes on a scale from 'very conservative' to 'very liberal'.
People with liberal views tended to have more grey matter in the anterior cingulated cortex, a region of the brain involved in decision-making, particularly when conflicting information is being presented.
Previous research has shown that electrical potentials recorded in this area during a task involving responding to conflicting information were greater in people who were more liberal or left wing than people who were more conservative.
Conservatives, meanwhile, appear to have increased grey matter in the amygdala, an area of the brain associated with processing emotion, particularly fear. This backs up studies showing that people who consider themselves to be conservative respond to threatening situations with more aggression than liberals.
The findings suggest that, at least to some extent, political persuasions are encoded in the structure of the brain. However, what's not clear is whether the changes in brain structure are the cause or the effect of political views.