Are political leanings imprinted in your genes?

The race to become the most powerful politician on earth is well under way, and the United States is gripped by election fever. In newsrooms and bars across the land, liberals and conservatives are slugging it out, trying to convince each other that their way of thinking is right.

They might be wasting their breath.

Emerging research suggests political positions are largely determined by biology and can be stubbornly resistant to reason.

"These views are deep-seated and built into our brains. Trying to persuade someone not to be liberal is like trying to persuade someone not to have brown eyes," says John Alford, a political scientist at Rice University in Houston.

Evidence to support this idea is growing. Studies suggest that opinions on a long list of issues, from religion in schools to nuclear power and gay rights, have a substantial genetic component.

The idea that our politics are in part shaped by our genes is not itself new, but it has only recently come to the attention of political scientists.

In 2005, Alford published a paper in American Political Science Review in which he analyzed two decades of work in behavioral genetics, including a huge database containing the political opinions of 30,000 twins from Virginia. He found that identical twins were more likely than nonidentical twins to give the same answers to political questions. For example, on the issue of whether property should be taxed, four-fifths of identical twins gave the same answer, compared to two-thirds of nonidentical twins.

What could account for this? Well, given that identicals have the same genes while nonidenticals share only half their genes, the results suggest the answer must be influenced by their genes.

The idea is startling. Evolution is a slow process that takes centuries to affect changes, so why would it endow us with genes that affect issues that seem fleeting on an evolutionary scale?

Frank Sulloway, a psychologist at the University of California, Berkeley, backs the idea that genes can influence political attitudes, but admits the results may sound odd. "There's no such thing as a gene for disliking hippies," he says. The point is that certain genes shape personality traits, and these are linked to political opinion.

In 2003, John Jost, a psychologist at New York University, and colleagues surveyed 88 studies involving more than 20,000 people in 12 countries that looked for a correlation between personality traits and political orientation. Jost uncovered some intriguing connections.

People who scored highly on a scale measuring fear of death, for example, were almost four times more likely to hold conservative views. Dogmatic types were also more conservative, while those who expressed interest in new experiences tended to be liberals. Jost's review also noted research showing that conservatives prefer simple and unambiguous paintings, poems and songs.

Jost noticed a pattern emerging from these results that fits neatly into existing models of personality. Many psychologists believe personality can be categorized into five classes, relating to conscientiousness, openness, extroversion, agreeableness and neuroticism. All of the big five personality traits are highly inheritable.

Scores on the conscientiousness scale show a significant correlation with position within the political spectrum. A much stronger link exists between political orientation and openness, which psychologists define as an ability to accept new ideas, a tolerance for ambiguity and an interest in different cultures. People with high openness scores turn out to be almost twice as likely to be liberals.

Some traits that are linked to openness, such as being sociable, are known to be influenced by the levels of neurotransmitters in the brain. And levels of these chemicals are controlled in part by genes.

Many other genes are likely to be involved. In a paper presented in April 2007 to the annual conference of the Midwest Political Science Association in Chicago, Ira Carmen, of the University of Illinois at Urbana-Champaign, discussed D4DR, a gene involved in regulating levels of the neurotransmitter dopamine. It is known that high levels of dopamine can cause obsessive-compulsive disorder.

Carmen speculates that dopamine might therefore be linked to the need to impose order on the world. If so, variants of the D4DR gene that lead to higher levels of dopamine should be found more frequently in conservatives. Carmen plans to apply for a grant to study this and other issues in around 200 or so individuals.

There is no shortage of critics who question the whole idea of linking politics with biology.

Personality studies in particular have been singled out as sloppy science, in part because traits like openness cannot be measured in the way that height or eye color can. To gauge personality, psychologists generate a series of questions designed to measure the trait of interest.

Asking a subject whether they "jump into things without thinking" is one way to measure openness. But some of the questions on the tests assess issues that are political in nature, such as a subject's views about foreigners. If this is the case, "the correlation is completely circular," says Evan Charney, a political scientist at Duke University, Durham, N.C.

Charney has a more general criticism of the personality work. As others have pointed out, a rather unflattering view of conservatives emerges from the studies. They are portrayed as dogmatic, routine-loving individuals, while liberals come across as free-spirited and open-minded folk.

Charney feels that inherent biases in the makeup of academia, which is dominated by liberals, leads to the "pathologizing of conservatism."

"It's hard to come up with totally unbiased language," admits Sulloway. However, Jost points out that conservative academics have run personality studies and come up with similar results. "We are all pretty much finding the same kinds of differences," he says.

Even if the personality differences between people who hold varying political views turn out to be real, others are skeptical we will ever understand the genetics that underlie them. Lindon Eaves, a behavioral geneticist at Virginia Commonwealth University in Richmond, helped assemble much of the data that Alford reviewed in 2004. He says that complex traits such as openness are likely to be determined by the combined action of a large number of genes.

We may soon find out whether Carmen and others will prove Eaves wrong. Next March, Carmen is inviting over 50 geneticists, politics researchers and neuroscientists to a conference at the University of Illinois at Urbana-Champaign to discuss such ideas, in the hope of giving birth to a whole new field of study.

So far, the research has attracted little attention outside academia. Of the researchers that New Scientist spoke to, none said that professional politicians had expressed an interest in their work. Some political think tanks know about the results, but view them with suspicion.

At the American Enterprise Institute, a pro-free-market group, scholar David Frum says that he is "flattered by the evidence that conservatives are more honest and dutiful than liberals." But given the huge number of variables that affect the outcome of an election, it would be a foolhardy researcher who would draw generalizations from Jost's work, he says.

Those involved in the research add that even if we do find genes that have a powerful influence on politics, it will still be worth having political debates. Alford says his work shows that our reaction to homosexuality is in part determined by our genes. But over time, he adds, policy still changes. Arguments over gay rights now focus on issues of discrimination at work and the right to marry.

Just 50 years ago, much of the debate was about whether homosexuality should be legal. The two sides still do not understand each other, but protest movements, media pressure and other factors have helped change the issues they fight over.

So the guy at the bar may never agree with you, but perhaps realizing that can be liberating. "We spend a lot of energy getting upset with the other side," says Alford. We often think our opponents are misinformed or stubborn. Accepting that people are born with some of their views changes that, Alford points out. Come to terms with these differences, and you can spend the energy now wasted on persuasion on figuring out ways of accommodating both points of view.