The study found that conservatives have a larger right amygdala. The amygdalae, of which there are two, one in each hemisphere of the brain, are associated with reactions to fear, the study said. On the other hand, liberals have a larger anterior cingulate cortex, or ACC.
Other studies had already determined that, based on liberal / conservatives views, those same sections of the brain had greater activity. This was the first such study to associate physical differences with political views.
Ryota Kanai of the University College London, where the research was done, said, "Previously, some psychological traits were known to be predictive of an individual's political orientation. Our study now links such personality traits with specific brain structure."
The study said, "We found that greater liberalism was associated with increased gray matter volume in the anterior cingulate cortex, whereas greater conservatism was associated with increased volume of the right amygdala."
Since the ACC , the study said, is a region that "monitor(s) uncertainty and conflicts," that could explain the individuals' more liberal views. "Thus, it is conceivable that individuals with a larger ACC have a higher capacity to tolerate uncertainty and conflicts, allowing them to accept more liberal views," the study said.
Meanwhile, those with a larger amygdala are "more sensitive to disgust" and tend to "respond to threatening situations with more aggression than do liberals and are more sensitive to threatening facial expressions," the study added. However, it is unclear if the physical differences in the brain cause the difference in political views, or are a result of the political views themselves.
The study was based on 90 "healthy young adults." These individuals reported their political views on a scale of one to five from very liberal to very conservative, then agreed to brains scans.
The study concluded, "Our findings are consistent with the proposal that political orientation is associated with psychological processes for managing fear and uncertainty." It has been said, previously, that the GOP preys on fear during its campaigns, and this may explain that course of action.