In this post, Aaron C. Weinschenk expands on his and his co-authors’ article in a recent issue of Politics and the Life Sciences.

Why are some people very interested and involved in politics while others could not care less and rarely, if ever, engage in political activities?

This has been a central question in political science for decades now. It has also been of interest to scholars in other fields, including psychology, sociology, and economics. For a long time, scholars believed that political engagement was largely a function of environmental factors such as family socialization. In the past fifteen years or so, though, researchers have started to take seriously the idea that political interest and participation might also be influenced by psychological and biological factors. In other words, political engagement might be the product of both nurture and nature.

In our recent paper “New evidence on the link between genes, psychological traits, and political engagement,” my co-authors and I set out to examine the connections between biology, psychology, and politics. Our interest in this topic stemmed from three lines of research. First, a recent body of work in the area of political psychology has shown that political interest and participation are partially heritable. Second, numerous studies in psychology and political science have shown that psychological traits are related to political attitudes and behaviors. Finally, decades of research in psychology has shown that many psychological traits are heritable. Based on these findings, we were interested to learn whether genes may be linked to political interest and engagement via different psychological traits.

To conduct our study, we used data from a large survey of German twins (the TwinLife Study), which contained measures of political engagement (interest in politics and participation in various activities) and several psychological traits (cognitive ability, agreeableness, extraversion, openness, self-efficacy, etc.). Data on same-sex twin siblings has traditionally been used to estimate the heritability of behaviors and attitudes. (A twin study leverages the fact that monozygotic twins share 100% of their genes, while dizygotic DZ twins share on average 50% of their genes. By comparing the trait similarity among MZ twin pairs to that of DZ twin pairs, we can obtain an estimate of the degree to which genes influence a given trait.)

As a starting point, we examined the extent to which psychological traits and political engagement were heritable. Consistent with previous studies, we found that both were moderately heritable. Next, we examined whether psychological traits and political engagement were related. We found that several of the traits in our study were positively correlated with political engagement. Two of the psychological traits that were the most strongly related to engagement were openness to experience and cognitive ability. Thus, we focused on these two psychological attributes. In the final part of our study, we examined whether the relationship between psychological traits and political engagement is primarily driven by environmental or genetic factors. Overall, we found that common genes account for a majority of the correlation between cognitive ability and political engagement. Openness to experience and political engagement were also influenced by the same set of genes.

There are a couple of ways to interpret our results. On one hand, significant genetic overlap between psychological traits and engagement could be taken to mean that psychological traits mediate the relationship between genes and political measures (this would imply a causal ordering). On the other hand, it is possible that psychological traits and political measures share the same underlying genetic mechanism but do not share a causal relationship. At this point, it is too early to say for sure exactly what the nature of the relationship is between genetic factors, psychological traits, and political engagement. With additional studies and new datasets (e.g., longitudinal twin studies), however, scholars should be able to develop a more nuanced understanding of how biology and psychology come together to influence political behavior.

The PLS article ‘New evidence on the link between genes, psychological traits, and political engagement‘ by Aaron C. Weinschenk, Christopher T. Dawes, Christian Kandler, Edward Bell and Rainer Riemann is available free of charge until the 15th of May 2020.