The genetics of political views

Why do we have the political views we have? It's always an interesting question. One angle which is less regularly explored is the influence of genetics on political views. Most people seem to have similar views to their parents, but there are usually convenient and intuitively plausible just-so stories as to why that is down to nurture, rather than nature.

I came across a paper from 2012 which lays out some of the results that psychologists and behavioural geneticists have come to in a clear and intuitive way. By Peter Hatemi and Rose McDermott and entitled "The Genetics of Politics: discovery, challenges and progress" it summarises findings in the literature most cleanly in its two diagrams.

We find that political knowledge is about 60% genetic, and 35% down to 'non-shared environment' (the environment people create for themselves rather than upbringing and schooling and so on), with only 5% identifiably down to upbringing. At the other end of the spectrum the specific party one identifies with is barely genetic at all, and comes overwhelmingly down to 'shared environmental influences' like schooling and parental nurture.

This is despite the fact that lots of traits you might think affected party affiliation (traditionalism, authoritarianism, foreign policy preferences and so on) are highly genetic.

Just how similar people with the same genes are politically is displayed below. Monozygotic, i.e. identical, twins are the pink bars and once they reach late adolescence, their political ideology correlates together with a coefficient of about 0.7 through their life! By contrast dizygotic, i.e. non-identical, twins are similarly close together politically while they live together with their parents and twin, but their correlation falls to about 0.4 as adults.

If it sometimes seems like no one ever changes their mind, and stays stuck to their guns, thinking up new arguments to defend their prejudices—well the science seems to agree with you.