Why Do People Vote? Genetic Sources of Political Participation

Why do people vote? “When one person votes, everyone with the same preferences benefits from the increased likelihood that their preferred outcome will result. Yet those who do vote must bear the coast of time and effort required to learn about election alternatives and go to the polls. In large populations, the probability that a single vote will change the outcome of an election is minuscule (..), meaning that even very small costs to the individual typically outweight the expected benefits he or she would receive from voting. As a result, classic game theoretic models that assume individuals are self-interested and fully optimizing in their behavior show that the equilibrium amount of voter turnout approaches zero as the population becomes large (..). Yet in spite of this theoretical result, millions of people do vote, suggesting behavior drives their decision (..). In addition, the fact that millions of people abstain suggest that there may be inherent variation in the human tendency to participate in politics.” [1]

I read some papers this evening that were published very recently in 2008 (Although the results are older, as e.g. indicated by an elder abstract published here by Adam Kolber in 2007). These papers claim to have found evidence of heritability of voting. A paper entitled Genetic Variation in Political Participation [1] by Fowler, Baker and Daws, who are with the University of California in San Diego, published in the May 2008 issue of The American Politicial Science Review, showed in two independent studies of twins that voter turnout has very high heritability. Their findings are conducted from evaluating data about 168 monozygotic who were conceived from a single fertilized egg and share 100 % of their genes, and 102 dizygotic twins who were conceived from two separate eggs and share only 50 % of their genes on average. The data has been gathered from twin registry and voter registration records in Los Angeles county. Moreover, data of a national representative sample was used for an independent replication of the results. Their findings can be summarised as follows [2]:

While the choice of a particular candidate or party does not appear to be heritable, a significant proportion of the variation in the decision to participate in politics can be attributed to genetic factors. Fowler, Baker, and Dawes (2008) recently studied the voting behavior of two populations of twins and showed that heritability accounted for 53% of the variation in validated turnout of those living in Los Angeles county and 72% of the self-reported turnout in a nationally representative sample of young adults. They also showed that heritability accounted for 60% of the variation in a general index of political participation, including contributing to campaigns, running for office, volunteering for political organizations, and attending protests. These results were the first to suggest that humans exhibit inherent variability in their willingness to participate in politics.

As discussed in the paper, these findings would help to explain why models based primarily on environmental variables fit poorly to observed behavior and it would conform to two well known features of voting: i) parental turnout behavior has been shown to be one of the strongest predictors of turnout behavior in young adults  and ii) turnout behavior has been shown to be habitual—the majority of people either always vote or always abstain (cf. [1]).

However, this paper does not address specific mechanism that links genes to participation. Thus, it merits further investigation to find out why genes matter so much.

The first paper beg the question which genes matter, which is addressed in a follow-up work by Fowler et al. entitled Two Genes Predict Voter Turnout, published in The Journal of Politics in July 2008. In this paper, the authors hypothesize “that people with more transcriptionally efficient alleles of the MAOA and 5HTT genes are more likely to vote” [2].

In summary: Fowler et al. [1, 2] claim to found evidence that genes do contribute to variation in turnout. Their results suggest that both genes and environmental influences matter, without specifying to which degree both factors affect turnout. They do not claim that genetic effects are more important than environmental effects.

What these paper are not about: These paper do not claim that the choice of an particular candidate is influenced by genetics. Moreover, these paper do not state that genetics are the only effect that influences turnout—genetics is one effect among others that influences turnout.

German speakers might find this post by Marc interesting.

References:
[1] James H. Fowler, Laura A. Baker, Christopher T. Dawes: “Genetic Variation in Political Participation“. In: The American Political Science Review, May 2008: Volume 102, No. 2
[2] James H. Fowler, Christopher T. Dawes: “Two Genes Predict Voter Turnout“. In: The Journal of Politics, Vol. 70, No. 3, July 2008, Pp. 579–594