a1 University of California, San Diego
a2 University of California, San Diego
a3 Harvard University
a4 University of California, San Diego
Scholars in many fields have long noted the importance of social context in the development of political ideology. Recent work suggests that political ideology also has a heritable component, but no specific gene variant or combination of variants associated with political ideology have so far been identified. Here, we hypothesize that individuals with a genetic predisposition toward seeking out new experiences will tend to be more liberal, but only if they are embedded in a social context that provides them with multiple points of view. Using data from the National Longitudinal Study of Adolescent Health, we test this hypothesis by investigating an association between self-reported political ideology and the 7R variant of the dopamine receptor D4 gene (DRD4), which has previously been associated with novelty seeking. Among those with DRD4-7R, we find that the number of friendships a person has in adolescence is significantly associated with liberal political ideology. Among those without the gene variant, there is no association. This is the first study to elaborate a specific gene-environment interaction that contributes to ideological self-identification, and it highlights the importance of incorporating both nature and nurture into the study of political preferences.
(Received January 16 2009)
(Accepted November 02 2009)
Jaime E. Settle is a Ph.D. candidate in the Department of Political Science, University of California, San Diego, 9500 Gilman Drive 0521, La Jolla, CA 92093-0521.
Christopher T. Dawes is a Ph.D. candidate in the Department of Political Science, University of California, San Diego, 9500 Gilman Drive 0521, La Jolla, CA 92093-0521.
Nicholas A. Christakis is a Professor of Health Care Policy, Harvard Medical School, and Department of Sociology, Harvard University, Cambridge, MA 02138.
James H. Fowler is a Professor of Genetics in the School of Medicine and Professor of Political Science in the Division of Social Sciences, University of California, San Diego, 9500 Gilman Drive 0521, La Jolla, CA 92093-0521.