Most Monkey-Cagers will be aware that there is a minor growth industry in articles arguing that genes may cause various political propensities and behaviors. Elizabeth Suhay and her colleagues have an interesting paper arguing that “twin studies (and in particular Alford et al. 2005) don’t show what they claim to”:http://sitemaker.umich.edu/suhay/files/critique_of_twin_studies_—_suhay__kalmoe__mcdermott_101007.pdf.
We present a critical analysis of Alford, Funk, and Hibbing’s “Are Political Orientations Genetically Transmitted?” (2005) and the twin study method on which it relies. We argue that the heritability statistics generated by classic twin studies are likely inflated because of violations of the Equal Environments
Assumption. Further, we argue that such twin studies shed little light on what causes human traits to develop: they focus on variation rather than causation and ignore nature / nurture interactions. Alford et al. provide misleading discussions of these limitations. They also make several specific genetic claims that are not empirically supported. In response to the authors’ undervaluation of social influences on ideology, we present data from the socialization literature on social transmission of political attitudes in the family. Finally, we propose a more useful theoretical framework for analyzing the complex, interacting relationships of biological and social influences on political orientations called constructivist interactionism.
I understand that twin studies get a fair amount of flak from professional statisticians; for further discussion see this post by Cosma Shalizi.