Lefty or righty? A new study links a larger anterior cingulate cortex (left) to politically liberal views and a larger right amygdala to conservatism. Image: R. Kanai et al., Current Biology, 21 (26 April 2011)
What makes someone a conservative or a liberal? According to this new (and undoubtedly controversial) study, it's their brain anatomy:
Cognitive neuroscientist Ryota Kanai and colleagues at University College London recruited 90 student volunteers and had them rate their political philosophy on a five-point scale ranging from very liberal to very conservative. Then the researchers used magnetic resonance imaging to get a look inside their brains. In a paper published online today in Current Biology, the team reports two main findings: political conservatives tend to have a larger right amygdala, a region involved in detecting threats and responding to fearful stimuli, whereas liberals tend to have a larger anterior cingulate cortex, an area that becomes active in situations involving conflict or uncertainty.
There was considerable overlap though. When the researchers looked only at the brain scans, Kanai says they could predict who was liberal and who was conservative with about 75% accuracy—much better than a coin toss but probably not good enough for any high-tech campaign tactics.
Kanai is at pains to make clear that the findings don't mean political views are "hard-wired" into the brain. He acknowledges that the data don't prove that these neuroanatomical differences actually cause political differences, but he suspects that they might play a role.