by Agence France-Presse April 7, 2011
WASHINGTON Everyone knows that liberals
and conservatives butt heads when it comes
to world views, but scientists have now shown
that their brains are actually built differently.
Liberals have more gray matter in a part of the
brain associated with understanding complexity,
while the conservative brain is bigger in the
section related to processing fear, said the
study on Thursday in Current Biology.
"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," the study said.
Other research has shown greater brain activity
in those areas, according to which political views
a person holds, but this is the first study to
show a physical difference in size in the same regions.
"Previously, some psychological traits were known
to be predictive of an individual's political
orientation," said Ryota Kanai of the University
College London, where the research took place.
"Our study now links such personality traits with
specific brain structure."
The study was based on 90 "healthy young adults"
who reported their political views on a scale of
one to five from very liberal to very conservative,
then agreed to have their brains scanned.
People with a large 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 said.
Liberals are linked to larger anterior cingulate
cortexes, a region that "monitor(s) uncertainty
and conflicts," it said.
"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."
It remains unclear whether the structural
differences cause the divergence in political
views, or are the effect of them.
But the central issue in determining political
views appears to revolve around fear and how
it affects a person.
"Our findings are consistent with the proposal
that political orientation is associated with
psychological processes for managing fear and
uncertainty," the study said.