An increasing number of studies suggest that biology can exert a significant influence on political beliefs and behaviours. Biological factors including genes, hormone levels and neurotransmitter systems may partly shape people’s attitudes on political issues such as welfare, immigration, same-sex marriage and war. And shrewd politicians might be able to take advantage of those biological levers through clever advertisements aimed at voters’ primal emotions.
In 1986, Nicholas Martin and his colleagues published a study1 suggesting that genes could exert a pull on attitudes concerning topics such as abortion, immigration, the death penalty and pacifism. Martin, a geneticist now at the Queensland Institute of Medical Research in Brisbane, Australia, used a classic behavioural-genetics technique: comparing genetically identical twins with fraternal twins of the same sex (who share only 50% of genes on average). The identical twins had similar political beliefs more often than fraternal twins did. Because twins tend to grow up in the same family environments, Martin’s team suggested that genes made the difference, and that they have a significant role in helping to shape attitudes on social issues.
Although Martin’s study had obvious implications for political science, researchers in that field ignored the work. The eugenics movement in the early part of the twentieth century and Nazi theories about the biology of human differences had made political scientists extremely wary about topics that examined genetic differences among people.
The publication “was like a stone down a well”, says Martin. “There was absolutely no reaction. It just lay there for 20 years.”
But in the early 2000s, Hibbing and John Alford, a political scientist at Rice University in Houston, Texas, learned about Martin’s work. They reanalysed his data and incorporated similar data from a study2 of attitudes among US twins. In 2005, Hibbing and Alford published3 findings nearly identical to those earlier studies — showing strong correlations between genetics and political views. These finally caught the attention of political scientists.
It wasn’t the kind of attention that Alford and Hibbing were hoping for, however. “They thought we were crazy,” says Hibbing.
But a few researchers, mainly in the United States, were intrigued enough to follow up with further work. James Fowler, a political scientist at the University of California, San Diego, used the twin method to show4 that voter turnout and political participation also had a genetic component. Peter Hatemi, a political scientist at Pennsylvania State University in University Park, found results similar to Alford and Hibbing’s using twins from Australia, Denmark, Sweden and the United States, although the work has not yet been published.
Twin studies also offer no insight into how the genome can nudge people to lean left or right on various political issues. For that, researchers have started exploring candidate genes. Genes involved with the olfactory system and the neurotransmitters glutamate, dopamine and serotonin have all been linked to behaviours such as voter turnout6 and ideology7, although these findings have come under scrutiny and are yet to be independently replicated.
If other complex behaviours and traits are any indication, the answer is not going to be simple. Even for traits known to have a very large genetic component, such as height, the evidence points to the influence of thousands of genes, each applying a feather-light force. So it seems unlikely that a small number of genes can push someone towards being a liberal activist, a social conservative or a libertarian.
Many researchers have come to the conclusion that it is premature to focus on the genetics of politics. “It doesn’t make sense to go after the most difficult part of the puzzle,” says Alford.
An easier approach is to investigate the pathways that might connect genes with political behaviours and attitudes. One connection that has been suggested is personality. US conservatives may not seem to have much in common with Iraqi or Italian conservatives, but many political psychologists agree that political ideology can be narrowed down to one basic personality trait: openness to change. Liberals tend to be more accepting of social change than conservatives. Some studies8 suggest that liberals tolerate more ambiguity and uncertainty, whereas conservatives are more decisive, conscientious and attracted to order.
Theoretically, a person who is open to change might be more likely to favour gay marriage, immigration and other policies that alter society and are traditionally linked to liberal politics in the United States; personalities leaning towards order and the status quo might support a strong military force to protect a country, policies that clamp down on immigration and bans on same-sex marriage. But some researchers baulk at such simple links between personality and ideology. Evan Charney, a political scientist at Duke University in Durham, North Carolina, points out that conservatives sometimes embrace change, such as proposals in the United States to alter the tax code and welfare system. He also says that he and most people in his field are liberals — an imbalance that could bias how they interpret connections between personality and politics.
Some researchers have sought to move beyond personality studies to evaluate how participants’ physiological reactions can influence how they interpret and respond to political issues. In 2008, Alford, Hibbing, Hatemi and others measured how people reacted to threatening images and sudden, loud noises9. People who blinked harder and showed heightened sensitivity — as gauged by their skin conductance — were more likely to favour gun rights, capital punishment and the war in Iraq than were those who showed less sensitivity.
“If people spend most of their lives focusing on negative rather than positive, they’re probably going to have a different way of experiencing the world.”
In another study10, Hibbing showed subjects a series of emotionally charged images, including a spider on a man’s face, a maggot-infested wound, a cute rabbit and a happy child. People who described themselves as conservatives tended to respond more strongly when looking at the negative images than at the positive images, whereas liberals reacted more to the positive pictures. Conservatives also stared at the negative images longer than liberals did, which Hibbing connects to the idea that conservatives are more likely to confront fearful or disgusting situations, making them more disposed to support a strong military and harsh sanctions for criminals.
Some researchers are exploring whether hormone systems play a part in political attitudes. A few studies, for example, have looked at connections between people’s prejudices and their levels of oxytocin — the feel-good hormone linked to empathy and bonding with loved ones. In one experiment11, Dutch participants who had taken puffs of oxytocin responded more favourably to Dutch people than to foreigners, suggesting a bias towards their own group.
Hatemi and Rose McDermott, a political scientist at Brown University in Providence, Rhode Island, are currently investigating whether other hormones, such as testosterone and cortisol, have any connections with ideology. Many of the hormone studies done so far have come under attack, because they often rely on small samples and the reported effects are sometimes weak.
- Martin, N. G. et al. Proc. Natl Acad. Sci. USA 83, 4364–4368 (1986).
- Lake, R. I., Eaves, L. J., Maes, H. H., Heath, A. C. & Martin, N. G. Behav. Genet. 30, 223–233 (2000).
- Alford, J. R., Funk, C. L. & Hibbing, J. R. Am. Polit. Sci. Rev. 99, 153–167 (2005).
- Fowler, J. H., Baker, L. A. & Dawes, C. T. Am. Polit. Sci. Rev. 102, 233–248 (2008).
- Smith, K. et al. Am. J. Polit. Sci. 56, 17–33 (2012).
- Fowler, J. H. & Dawes, C. T. J. Polit. 70, 579–594 (2008).
- Settle J. E., Dawes, C. T., Christakis, N. A. & Fowler, J. H. J. Polit. 72, 1189–1198 (2010).
- Carney, D. R., Jost, J. T., Gosling, S. D. & Potter, J. Polit. Psychol. 29, 807–840 (2008).
- Oxley, D. R. et al. Science 321, 1667–1670 (2008).
- Dodd, M. D. et al. Phil. Trans. R. Soc. B 367, 640–649 (2012).
- De Dreu, C. K. W., Greer, L. L., Van Kleef, G. A., Shalvi, S. & Handgraaf, M. J. J. Proc. Natl Acad. Sci. USA 108, 1262–1266 (2011).
- Bonanno, G. A. & Jost, J. T. Basic Appl. Soc. Psychol. 28, 311–323 (2006).
- Helzer, E. G. & Pizarro, D. A. Psychol. Sci. 22, 517–522 (2011).
Lizzie Buchen, Biology and ideology: The anatomy of politics. Nature 490, 466–468 (25 October 2012) doi:10.1038/490466a