The Genetics of Politics

Great discussion over at the Corner on this NYT article, (misleadingly -- surprise!) entitled "Some politics may be etched in the genes." I think it is most interesting, and (meta-)relevant to this discussion, that the distinctive political personalities of Jonah and the Derb were so clearly manifest in their debate. Although each made good points and the two ultimately had much agreement, I saw Jonah as being characteristically more dismissive of this sort of novelty, and thus more optimistic about the study's low likelihood of undermining his ideals, while John's conservatism often appears born of his inclination to see things a bit more darkly, and accept that his ideals will and must struggle against a hard reality. (NOTE: I hope I am being fair to each, as I tend to oscillate between these two conservatisms myself.)

So far, though, only My Pet Jawa seems to have read the actual article in American Political Science Review (Jonah's e-mailer had the article in front of him, but unfortunately mischaracterized the contents in several ways). Jawaprovides a pretty detailed summary of the article, which compares monozygotic (identical) twins to dizygotic (fraternal twins) on a survey of political attitudes. To make a long story short, the authors of the article demonstrate that MZ twins, who are genetically identical, have much greater "ideological" agreement than DZ twins, who are only as genetically similar as any 2 siblings (about 50% genetic similarity on average).

I think that the findings themselves appear to be robust, as the sample size is enormous, and the findings are generally well-replicated in a second sample of Australian twins. Further, the influence of parental attitudes is accounted for (albeit in a very narrow statistical sense, and only for a limited subsample). I think it is indisputable that the study shows that MZ twins have more political agreement (on certain survey items phrased in a particular way) than DZ twins.

So, the sticky wicket is the interpretation. The authors use a mathematical approach to defining heritability that has been widely-used in behavioral genetics (though never before in political science per se), but is very controversial philosophically and is prone to misinterpretation. In a nutshell, the mathematics superficially ascribe discrete packets of causality (percentages of variance explained) to genes, shared (familial) environment, and external events (unshared environment). Yet it is a fundamental philosophical error to reify these constructs, and a whopping scientific error to ignore the centrality of interaction effects. Any of these potential subtleties are, predictably, almost completely lost on the hapless NYT reporter, as ShrinkWrapped correctly details.

However, the authors of the APSR article are actually much more sophisticated in their approach than the NYT, especially in their introduction. They clearly point out how genes "provide instructions for the production of proteins," which then are expressed in the brain, leading to a cascade of biological events that may ultimately be manifest in behavior; thus, it is absurd to infer that genes would ever specifically encode for substantive policy beliefs. Moreover, they use examples from the most up-to-date psychiatric literature to emphasize the role of gene-gene and gene-environment interactions. For example, a particular variant in the serotonin transporter gene only results in increased risk for depression when the individual is exposed to highly stressful life events. Individuals with the risk variant who do not experience as much trauma do not manifest depression. (Another popular example, not cited in the article, is the role of genetics in smoking behavior. Several decades ago, when most men smoked and very few women were smokers, smoking behavior was less genetically determined than today, in which a very different social environment has made it more likely that predisposed-women will smoke, and non-predisposed men will not.)

These points cannot be emphasized enough, and at some point the MSM is going to have to figure out how to convey them. As I hinted in a previous post, there are certain newly-emerging biological facts that the public will soon be forced to reckon with, and the MSM need to be the first to do so or must step aside. At best, it will be like that period in 1997-98, when the NY Times had to slug the same stock paragraph explaining "The Internet" into just about every article.

Where the authors go off the rails is in their conclusions, where they seem to have been swept away by their own data, and ignore the caveats of their own introduction. They also seem to have two pages worth of liberal propaganda, which reveals either their own biases or was required by the journal's editor and reviewers for publication. The following quote, picked up also by Jawa, is illustrative:

Similarly,if a Republican president had committed adultery with a young intern or if a Democratic president had dramatically worsened the deficit and taken
the country to war in a far-off land on the basis of undeniably incorrect beliefs about the opponents' nuclear and chemical weapons capabilities, the positions of most voters on the acceptability of these conditions would be completely reversed.

It is getting very late, and this post is getting very long, so I will pick up on this point later, in a post to be entitled: The Politics of Genetics.