The sociological fad for seeking straightforward biological bases for complex social phenotypes has spread in recent years to political science. A recent collection of articles and blog posts rehashes the rhetoric that garnered widespread criticism in sociology. Essentially the scholarship establishes an entirely noncontroversial position–that biological influences on political ideology are “nonzero”–and spins this into the much broader, and indefensible, claim that inter-person variation in biology is (a) unidirectionally causal; and (b) a significant source of variation in political ideology.
Erik Voeten writes here and here about Fowler and Dawes’ study (gated, sorry) of the effects of specific genotypes–two genes in particular–on voter turnout that exemplify the common rhetorical leap. The study he refers to can reasonably be held to demonstrate that “these two genes might matter a little in influencing voter turnout”, but far from the causal home run implied by the article’s title (“Two Genes Predict Voter Turnout”). Essentially, these two genes — MAOA and 5HTT — show modest effects on voter turnout, likely because of their role in regulating serotonin, a crucial and multipurpose neurotransmitter. Serotonin is implicated in a huge array of social and emotional phenomena, and these likely cluster in ways that result in modest but discernible effects on voter turnout.
Verhulst et al. argue in their recent AJPS article that personality traits do not in themselves cause political ideology but “the primary connection between personality traits and political ideology rests on common genetic precursors of each” (p. 48). Similarly, Hatemy and McDermott call for bringing physiological psychology (which “attempts to explain behavior by studying the physiological processes that control it,” p. 17) into the study of politics. Still, they hedge:
There is no single “gene” that “causes” any particular social behavior. Rather, the nuanced interaction of countless genetic markers contributes to the regulation of complex neurobiological pathways designed to receive, and remain exquisitely sensitive to, a vast array of both internal and external inputs. Genetic factors may indirectly predispose certain individuals toward particular traits or characteristics under certain conditions through genetic expression (epigenetics), and the regulation of hormones that change states of emotion, cognition, and biochemistry which begin with some social or environmental stimulus. And these environments can be global, local, or even within the cell. However, even in the case of a seemingly straightforward characteristic such as height, many different factors, such as in utero influences and childhood nutrition, combined with epigenetic mechanisms, contribute to any given phenotypic outcome…. attitudes and behaviors represent the expression of series of neurobiological processes informing cognitive and emotive mechanisms which interact with the environment. (p. 21)
Similarly in Smith et al.’s AJPS article:
What we actually observe is a pattern of relatively stable MZ [monozygotic twin] correlations…. at more typical levels of genetic similarity, environmental factors contribute more to political similarity. Our analyses are thus consistent with a susceptibility jmodel, i.e., the heritable underpinnings of adult ideology operate largely by creating varying levels of susceptibility to specific sorts of ideological appeals.
The Smith et al. article’s title promises epistemology, but little is to be found. Mostly it considers the so-called Equal Environments Assumption (EEA). This is the assumption that differences in environmental experiences (pre- and post-natal) between MZ (“identical”) and DZ (“fraternal”) twins do not affect outcomes of interest. Generally defenses of the EEA, including this one, do not deny that there are important and systematic differences in environment but claim that these are insufficient to explain greater similarity between MZ than DZ twins. However what would constitute “sufficient” causes is not specified, and there is reason to think, from economics as well as life-course sociology, that small causes may iterate into large outcomes. Still, the conclusion is hard to quibble with: “nothing in the EEA critique credibly supports [sic, I assume] a claim that genetic influence on political temperament is nonzero or non-trivial. ”
An important defender of the biopolitical paradigm, Larry Arnhart, sums up his position thus:
biopolitical science must be a complex science of emergent evolution that embraces not only genetic evolution but also the cultural history of political regimes and the individual history of political actors. Human genetics constrains but does not determine human cultures and human judgments.
Once again, this is a nearly entirely unobjectionable, but also not very interesting, claim about genetic influence. The rhetorical pattern is very common: assert that biological basic processes are important precursors of political ideas or behavior, accuse skeptics of being head-in-the-sand anti-science types (as Kieran so well undermined), and then demonstrate a minor finding that violates epistemological principles about causality and holds that the environment remains likely the dispositive cause.
I do not doubt that biological factors influence social and political outcomes. However, I think:
- These factors are not necessarily unidirectional; for example, environmental cues likely affect the production and uptake of serotonin and, therefore, the behavior of genetically-cued behaviors including but not limited to voting. So the relationship between environment and genes is almost certainly not a simple interaction (as in GxE) but likely a chain of indederminate length of genetic and environmental co-causes.
- Because of this chain character, the very practice of estimating heritability is not just imprecise but literally, epistemologically, impossible. All complex behaviors are 100% genetic and 100% environmental, and the task of partitioning variance is therefore an exercise in shoveling fog. To extend Arnhart’s statement: it is impossible to contemplate the practice of voting without a whole host of common human traits that are certainly evolved (the capacity for causal reasoning, vision, locomotion, opposable thumbs, and so on). It is also impossible to contemplate the practice of voting without a historically-contingent regime of subjectivity, individuality, etc., that is certainly discursive and environmental. Each has conditioned the other, iteratively, over the course of human history.
I got the metaphor from Courtney Bender’s The New Metaphysicals which has nothing at all to do with this topic.