Political Orientations Are Correlated with Brain Structure in Young Adults

Substantial differences exist in the cognitive styles of liberals and conservatives on psychological measures 1Jost J.T. Glaser J. Kruglanski A.W. Sulloway F.J. Political conservatism as motivated social cognition.Psychol. Bull. 2003; 129: 339-375Crossref PubMed Scopus (3032) Google Scholar. Variability in political attitudes reflects genetic influences and their interaction with environmental factors 2Alford J. Funk C. Hibbing J. Are political orientations genetically transmitted?.Am. Polit. Sci. Rev. 2005; 99: 153-167Crossref Scopus (595) Google Scholar, 3Settle J.E. Dawes C.T. Christakis N.A. Fowler J.H. Friendships moderate an association between a dopamine gene variant and political ideology.J. Polit. 2010; 72: 1189-1198Crossref PubMed Scopus (93) Google Scholar. Recent work has shown a correlation between liberalism and conflict-related activity measured by event-related potentials originating in the anterior cingulate cortex 4Amodio D.M. Jost J.T. Master S.L. Yee C.M. Neurocognitive correlates of liberalism and conservatism.Nat. Neurosci. 2007; 10: 1246-1247Crossref PubMed Scopus (386) Google Scholar. 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 4Amodio D.M. Jost J.T. Master S.L. Yee C.M. Neurocognitive correlates of liberalism and conservatism.Nat. Neurosci. 2007; 10: 1246-1247Crossref PubMed Scopus (386) Google Scholar and recognition of emotional faces 5Vigil J.M. Political leanings vary with facial expression processing and psychosocial functioning.Group Process. Intergroup Relat. 2010; 13: 547-558Crossref Scopus (69) Google Scholar 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 4Amodio D.M. Jost J.T. Master S.L. Yee C.M. Neurocognitive correlates of liberalism and conservatism.Nat. Neurosci. 2007; 10: 1246-1247Crossref PubMed Scopus (386) Google Scholar, 6Rule N.O. Freeman J.B. Moran J.M. Gabrieli J.D.E. Adams Jr., R.B. Ambady N. Voting behavior is reflected in amygdala response across cultures.Soc. Cogn. Affect. Neurosci. 2010; 5: 349-355Crossref PubMed Scopus (65) Google Scholar to suggest a possible link between brain structure and psychological mechanisms that mediate political attitudes.