The April 7th issue of "Current Biology" reports on an interesting finding, mainly that Individuals who call themselves liberal tend to have larger anterior cingulate cortexes (the part of our brain that is used when we deal with uncertanity and coping) while those who call themselves conservative have larger amygdalas (the fear center of the brain, used also in determining the emotions of others). The research came about from earlier studies that showed greater anterior cingulate cortex response to conflicting information among liberals.
What does all of this mean? Basically it accounts for why conservatives are more sensitive to threat or anxiety in the face of uncertainty, while liberals tend to be more open to new experiences.
The study occured in London, with MRI's performed on students who defined themselves as liberal or conservative. Obviously there are potential problems with the study (The population studied were younger--so its uncertain how representitive the results would be in a more divergent population; conservativism vs. liberalism is not a simple dichotic concept, some people can be liberal on some issues, conservative on others; it in no way speaks to what came first the extra brain matter or one's political ideology.)
However it does reveal some interesting areas for further study, on different populations to see if the trend holds.
The papers self-stated summary is provided below:
Substantial differences exist in the cognitive styles of liberals and conservatives on psychological measures [1]. Variability in political attitudes reflects genetic influences and their interaction with environmental factors [[2] and [3]]. Recent work has shown a correlation between liberalism and conflict-related activity measured by event-related potentials originating in the anterior cingulate cortex [4]. Here we show that this functional correlate of political attitudes has a counterpart in brain structure. In a large sample of young adults, we related self-reported political attitudes to gray matter volume using structural MRI. 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. These results were replicated in an independent sample of additional participants. Our findings extend previous observations that political attitudes reflect differences in self-regulatory conflict monitoring [4] and recognition of emotional faces [5] by showing that such attitudes are reflected in human brain structure. Although our data do not determine whether these regions play a causal role in the formation of political attitudes, they converge with previous work [[4] and [6]] to suggest a possible link between brain structure and psychological mechanisms that mediate political attitudes
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