James M Sherlock

Great (Ape) Expectations

Do You Share Political Preferences With Your Parents?

The hidden role of genes in political party preferences

Posted Feb 01, 2016

Michael Vadon/Flickr Creative Commons
Source: Michael Vadon/Flickr Creative Commons

Politics are a hot topic all over the world right now. In Europe, liberal and conservative parties are currently butting heads over how to handle a migrant crisis, while in the United States Donald Trump is unashamedly running for president on a platform of xenophobia and bigotry. Chances are that if you’re familiar with these issues you fall firmly on one side or the other with varying degrees of intensity. But where do these values come from? Is it our education? Our upbringing? Our friends and peers? Can they change or are they fixed? And why does almost every political system seem to exist on a bipolar spectrum of conservative to liberal?

Theresa Thompson/Flickr Creative Commons
Source: Theresa Thompson/Flickr Creative Commons

Social psychologists have gone someway to answering these questions by studying relationships between parents’ political preferences and their children's. However, often neglected in this research is the role of genes. For some it may seem inappropriate to use genetics to study political orientation, given that some of history’s more unsavoury political regimes have used a crude misunderstanding of genetics to support discriminatory policies (e.g. eugenics in Europe and the United States). Ironically, genetics have much to offer in the way of understanding how seemingly reasonable members of the public may come to support such positions while others reject them. The genetics of political preference may allow us to understand why some individuals gravitate towards authoritarian, often religious, conservatives who prioritise traditional values while others tend towards more liberal policy makers who focus on personal freedoms and equality over maintaining norms and structure. Further, with greater insight into the origins of our political preferences, we gain greater power to change them.

Key to investigating genetic influences on a trait is the use of twins. Because identical twins share all of their genes, they can be compared with non-identical twins who only share half of their genes. If a given trait is shared more strongly between identical twins than non-identical twins, it is likely that genes are influencing that trait. If, however, identical twins and non-identical twins are equally similar, it’s likely that the environment shared by the twins plays a significant role. By employing structural equation modelling, researchers can precisely estimate the proportion of variation in a trait that is due to their genes and to the environment shared by the twins. Importantly, the shared environment includes aspects of the home such as the political leanings of the parents, as well as parenting styles and socioeconomic status. Of course, any aspects of the trait not shared by the twins may be due to their own individual experiences, error in measuring the trait, or chance biological effects. This method has since been applied to thousands of traits across numerous fields of research.

Recently, a team of researchers collated the results of nearly 3,000 such studies and analysed the outcomes. Unsurprisingly, when it comes to social values the shared environment plays a large role, accounting for nearly 30% of the variation therein. What might be surprising is that the influence of genes was around the same size – 30% of the variation (Polderman et al., 2015).

Taking a more fine-grained approach, several teams of researchers have measured twins’ level of conservatism by polling their position on a number of social issues commonly linked to political outlook. The first of such studies was conducted in 1986 and included questions pertinent to the time period such as views relating to working mothers, co-education and mixed-race marriages. For the majority of the issues polled, genetic influences actually outweighed the shared environment of the twins (Martin et al., 1986). Similar results were observed in a later 2005 study of nearly 20,000 twins, with 43% of the variation in conservatism being accounted for by genes in contrast to just 22% caused by the shared environment (Alford, Hunk, & Hibbing, 2005).

Further research has focused on ideologies relating to right-wing authoritarianism, which constitutes a strong preference for social tradition consistent with political conservatism. Again, strong genetic influences were found, accounting for nearly half the variation in the trait (Lewis and Bates, 2014; Kandler, Lewis, Feldhaus, & Riemann, 2015).

Of course, it is supremely unlikely that our genes are somehow coding for conservative or liberal party preferences. It’s more likely that there are underlying psychological factors that align with the types of policies being espoused by the left or the right. Likely, these psychological factors are highly influenced by genes. For example, the heritability of political orientation been measured more recently by using measures that tap into either acceptance of inequality (anti-liberal) or acceptance of system change (anti-conservative). While the shared environment was only responsible for 9 and 10% of variation in these political factors, genes accounted for 20 and 40% of the variance (Costa & McCrae, 2008). In an Australian study, it was found that 24% of the variance in preferences for liberal or conservative government was due to genes. Interestingly, most of the variation in preferences was due to favouring or rejecting socialist principles (Hatemi et al., 2007).

John Kittelsrud/Flickr Creative Commons
Source: John Kittelsrud/Flickr Creative Commons

So where does this leave us? Political ideology may be heritable, but does that mean it is deterministic? Not necessarily.

On one level, genetically influenced attitudes may be more resistant to change. For example, in a small lab study participants had their political attitudes measured before and after engaging in group discussions of those issues (Bourgeois, 2002). Those attitudes that were substantially genetically influenced were less likely to change in discussion and this has since been replicated in more recent research (Schwab, 2014). In a more naturalistic study, the same researcher investigated how university campus residences could change political attitudes. For the most part, individuals’ attitudes tended to cluster together based on the halls that they were living in. However, those attitudes that were heritable were less likely to cluster and more likely to resist.

This seems like bad news for the malleability of political attitudes, but there’s still hope. Firstly, the shared environment (i.e. aspects of the home) still contributes to the formation of political orientation, which indicates that non-genetic factors play a significant role. Secondly, and perhaps more importantly, is the role of individual experience.

In none of the studies cited above was the entirety of political preference accounted for. In most cases a large portion of this variance was left unexplained by genetic influences or aspects of the home. It is here that individuals’ unique experiences will account for a major role in establishing political preference. We must hope that it is critical thought and sound reasoning that contributes to this last piece of the political puzzle, and not dogma or DNA.

Alford, J. R., Funk, C. L., & Hibbing, J. R. (2005). Are political orientations genetically transmitted? American political science review, 99(02), 153-167

Bourgeois, M. J. (2002). Heritability of attitudes constrains dynamic social impact. Personality and Social Psychology Bulletin, 28(8), 1063-1072. doi:10.1177/01461672022811005

Kandler, C., Lewis, G. J., Feldhaus, L. H., & Riemann, R. (2015). The genetic and environmental roots of variance in negativity toward foreign nationals. Behavior Genetics, 45(2), 181-199.

Lewis, G. J., & Bates, T. C. (2014). Common heritable effects underpin concerns over norm maintenance and in‐group favoritism: Evidence from genetic analyses of right‐wing authoritarianism and traditionalism. Journal of Personality, 82(4), 297-309.

Martin, N. G., Eaves, L. J., Heath, A. C., Jardine, R., Feingold, L. M., & Eysenck, H. J. (1986). Transmission of social attitudes. Proceedings of the National Academy of Sciences of the United States of America, 83(12), 4364-4368. doi:10.1073/pnas.83.12.4364.

Polderman, T. J. C., Benyamin, B., de Leeuw, C. A., Sullivan, P. F., van Bochoven, A., Visscher, P. M., & Posthuma, D. (2015). Meta-analysis of the heritability of human traits based on fifty years of twin studies. Nature Genetics, advance online publication. doi:10.1038/ng.3285.

Schwab, N. (2014). Social influence constrained by the heritability of attitudes. Personality and Individual Differences, 66(0), 54-57. doi: http://dx.doi.org/10.1016/j.paid.2014.03.011.