"Long before it's in the papers"
April 11, 2011

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Political views reflected in brain structure, scientists find

April 8, 2011
Courtesy of Cell Press
and World Science staff

We all know that peo­ple at op­po­site ends of the po­lit­i­cal spec­trum of­ten can’t see eye to eye. Now, a study has found those dif­fer­ences are tied to varia­t­ions in the very struc­tures of our brains.

Peo­ple who de­scribe them­selves as con­serv­a­tive tend to have a larg­er amyg­dala, a brain struc­ture linked to threat rec­og­ni­tion, sci­en­tists found. And those who call them­selves lib­er­al tend to have a larg­er an­te­ri­or cin­gu­late cor­tex, a struc­ture in­volved in cop­ing with con­flict­ing in­forma­t­ion.

The study was pub­lished April 7 on­line in the re­search jour­nal Cur­rent Bi­ol­o­gy.

“Pre­vi­ously, some psy­cho­log­i­cal traits were known to be pre­dic­tive of an in­di­vid­u­al’s po­lit­i­cal ori­enta­t­ion,” said re­searcher Ry­ota Kanai of the Un­ivers­ity Col­lege Lon­don. “Our study now links such per­son­al­ity traits with spe­cif­ic brain struc­ture.”

Kanai said his study was prompted by re­ports from oth­ers show­ing great­er an­te­ri­or cin­gu­late cor­tex re­sponse to con­flict­ing in­forma­t­ion among lib­er­als. “That was the first neu­ro­sci­en­tif­ic ev­i­dence for bi­o­log­i­cal dif­fer­ences be­tween lib­er­als and con­serv­a­tives,” he ex­plained. There had al­so been stud­ies show­ing con­serv­a­tives are more sen­si­tive to threat or anx­i­e­ty in the face of un­cer­tain­ty, while lib­er­als tend to be more open to new ex­pe­ri­ences. Kanai’s team sus­pected that such fun­da­men­tal dif­fer­ences in per­son­al­ity might show up in the brain.

That’s what they in­deed found. Kanai said they can’t yet say for sure which came first: it’s pos­si­ble that brain struc­ture is­n’t set in early life, but rath­er can be shaped over time by our ex­pe­ri­ences. And, of course, some peo­ple have been known to change their views. 

Moreo­ver, con­serv­a­tive vs. lib­er­al is by no means the only way to clas­si­fy our po­lit­i­cal per­sua­sions. 

“In prin­ci­ple, our re­search meth­od can be ap­plied to find brain struc­ture dif­fer­ences in po­lit­i­cal di­men­sions oth­er than the sim­plis­tic left- ver­sus right-wingers,” Kanai said. Per­haps dif­fer­ences in the brain ex­plain why some peo­ple really have no in­ter­est in pol­i­tics at all or why some peo­ple line up for Macs while oth­ers stick with their PCs, he added.

Kanai cau­tioned against tak­ing the find­ings too far, cit­ing many un­cer­tain­ties. “It’s very un­likely that ac­tu­al po­lit­i­cal ori­enta­t­ion is di­rectly en­cod­ed in these brain re­gions,” he said. “More work is needed to de­ter­mine how these brain struc­tures me­di­ate the forma­t­ion of po­lit­i­cal at­ti­tude.”

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We all know that people at opposite ends of the political spectrum often can’t see eye to eye. Now, a study has found those differences are tied to variations in the very structures of our brains. People who describe themselves as conservative tend to have larger amygdalas, a brain structure linked to threat recognition, scientists found. And those who call themselves liberal tend to have larger anterior cingulate cortexes, a structure involved in coping with conflicting information. The study was published April 7 online in the research journal Current Biology. “Previously, some psychological traits were known to be predictive of an individual’s political orientation,” said researcher Ryota Kanai of the University College London. “Our study now links such personality traits with specific brain structure.” Kanai said his study was prompted by reports from others showing greater anterior cingulate cortex response to conflicting information among liberals. “That was the first neuroscientific evidence for biological differences between liberals and conservatives,” he explained. There had also been studies showing conservatives are more sensitive to threat or anxiety in the face of uncertainty, while liberals tend to be more open to new experiences. Kanai’s team suspected that such fundamental differences in personality might show up in the brain. That’s what they indeed found. Kanai said they can’t yet say for sure which came first: it’s possible that brain structure isn’t set in early life, but rather can be shaped over time by our experiences. And, of course, some people have been known to change their views. Moreover, conservative vs. liberal is by no means the only way to classify our political persuasions. “In principle, our research method can be applied to find brain structure differences in political dimensions other than the simplistic left- versus right-wingers,” Kanai said. Perhaps differences in the brain explain why some people really have no interest in politics at all or why some people line up for Macs while others stick with their PCs, he added. Kanai cautioned against taking the findings too far, citing many uncertainties. “It’s very unlikely that actual political orientation is directly encoded in these brain regions,” he said. “More work is needed to determine how these brain structures mediate the formation of political attitude.”