Published online by Cambridge University Press: 08 March 2021
Twin studies function as natural experiments that reveal political ideology’s substantial genetic roots, but how does that comport with research showing a largely nonideological public? This study integrates two important literatures and tests whether political sophistication – itself heritable – provides an “enriched environment” for genetic predispositions to actualize in political attitudes. Estimates from the Minnesota Twin Study show that sociopolitical conservatism is extraordinarily heritable (74%) for the most informed fifth of the public – much more so than population-level results (57%) – but with much lower heritability (29%) for the public’s bottom half. This heterogeneity is clearest in the Wilson–Patterson (W-P) index, with similar patterns for individual index items, an ideological constraint measure, and ideological identification. The results resolve tensions between two key fields by showing that political knowledge facilitates the expression of genetic predispositions in mass politics.
The data employed in this project were collected with the financial support of the National Science Foundation in the form of SES-0721378, PI: John R. Hibbing; Co-PIs: John R. Alford, Lindon J. Eaves, Carolyn L. Funk, Peter K. Hatemi, and Kevin B. Smith, and with the cooperation of the Minnesota Twin Registry at the University of Minnesota, Robert Krueger and Matthew McGue, Directors. The data, code, and any additional materials required to replicate all analyses in this article are available at the Journal of Experimental Political Science Dataverse within the Harvard Dataverse Network, at: https://doi.org/10.7910/DVN/NBIWOA. Due to Martin Johnson’s passing during revisions, we are unable to post the replication files for the main OpenMX analysis, which we could not find among his files. There are no conflicts of interest to report.