In part 1 of this series I referenced the paper “The genetics of politics: discovery, challenges, and progress,” a review of years of research on genetic influences on political attitudes, and discussed the general concept of heritability. Now let’s get to the interesting stuff, namely the findings discussed in the paper.

Let’s start with the opposite ends of the spectrum. Per figure 1 in the paper (see Razib Khan’s post for a more readable version) some of the most heritable traits include having an interest in politics, voting and otherwise participating in politics, identifying as liberal or conservative, and political knowledge and sophistication in general. On the other hand the least heritable trait was party affiliation, which appeared to be much more influenced by one’s family and other shared environment. How can we reconcile this?

I haven’t read the referenced papers showing these results, but my off-the-cuff thought is that the more heritable traits are those related to underlying traits that are themselves fairly heritable, most notably innate moral intuitions (which could influence liberal vs. conservative leanings—see below for more on this) and general intelligence (which could influence the extent of one’s political knowledge and sophistication). On the other hand actual party affiliation is much more influenced by one’s family or close associates: We all know people who take their cues on which party and candidates to support from their spouses, parents, or friends; in some cases they may have minimal interest in politics, while in other cases they may simply “go along to get along” when it comes to publicly affiliating with a political party.

This relates to another finding reviewed in the paper (see figure 2), namely that “genetic influences on attitudes are expressed only when powerful social pressures, such as the parental environment, are no longer present. . . . Starting at age 21, . . . ideology emerges as being genetically influenced.” In other words, while children are most subject to the influence of their parents they are likely to mimic both the parents’ party affiliations and ideological beliefs (e.g., identifying as a liberal or conservative), independent of any genetic factors. (For example, the children may be adopted or have a stepparent.) However once children are fully independent their ideological beliefs shift to be more influenced by genetic factors, even as they may retain their parents’ party affiliation.

Let’s go back to the general question of why political attitudes might be genetically influenced (to greater or less degrees). As noted in the paper, presumably this is because present political issues relate to situations humans encountered in their long evolutionary history as social animals: under what circumstances should people cooperate, how should people balance the threats and opportunities inherent in encounters with others, how to reconcile personal desires with the demands of a social dominance hierarchy, and so on.

Although it’s not referenced by the paper, one way to look at this is through the “moral foundations” theory promoted by psychologist Jonathan Haidt and his colleagues (and popularized by Haidt in his book The Righteous Mind). The basic idea is that political attitudes ultimately rest on several “innate and universally available psychological systems” (the “foundations”) that people consider to be of more or less importance, and that these foundations are themselves genetically influenced as a result of human evolution.1

For example, in relation to the “fairness/cheating” foundation some people strongly believe individuals should and do get what they deserve (“fairness as proportionality”) while others are more concerned that everyone share with each other (“fairness as equality”). Looking back this connects to theories on how humans evolved to cooperate with one another: Those who cooperate realize mutual advantages, but in a society dominated by cooperators there are also advantages to exploiting others’ generosity; in response cooperators would benefit by evolving propensities to search for and punish instances of free riding. In the present day this influences political attitudes toward “welfare” as a general concept.

Similarly, attitudes around group loyalty and betrayal hark back to the need of groups to protect against attacks by other groups, a need that was balanced against the advantages (e.g., from trade) of interacting with others. In the present day these attitudes influence people’s positions on such issues as immigration, foreign policy, multiculturalism, and the like. Note that this doesn’t mean that loyalty to one’s group automatically translates into opposition to “out-groups.” It’s more that greater or lesser genetic predispositions to in-group loyalty combine with social learning (e.g., who’s in your group and who’s not) and particular circumstances (e.g., regional or national economic conditions) to influence an individual’s position on a particular issue (e.g., amnesty for illegal immigrants who are long-time US residents).

I could continue with more examples, but this is a good place for me to stop and formulate some final thoughts on the implications of all this. More on that in part 3.

  1. The New York Times review of The Righteous Mind has a good summary of Haidt’s arguments. ↩︎