A Nation Divided, In Perpetua?

Yet scientists are now discovering that our political attitudes have deep roots in our biology. Our place on the political spectrum – liberal, conservative, or in between – is powerfully influenced by genetics, new studies show. In the past year, researchers have demonstrated that the brains of liberals and conservatives are physically and functionally distinctive, suggesting that people on either side of the ideological divide are actually wired differently. And new research, published this fall in the prestigious journal Science, found that our immediate, unconscious reaction to threat – how much we startle at frightening images and noises – determines our political views on specific issues like gun control, national defense, the Iraq war, domestic surveillance, the torture of political prisoners, and even immigration.

“Political reactions are gut responses rather than a rational weighing of pros and cons,” said Kevin Smith, a University of Nebraska political scientist who coauthored the Science study. “Our research shows that these reactions are so deep-seated, they’re partly biological. Our biological makeup contributes to our political attitudes.”

The work of Smith and his colleagues is driving an emerging field, sometimes called “political physiology,” that challenges traditional views of politics. There is still room for a considered examination of issues. But the new research suggests we are not merely swayed, here and there, by emotional appeals. Our fundamental political framework is shaped by gut feelings with deep biological roots. Much of the research into political ideology points to the central role of the limbic system, which contains some of the brain’s oldest structures, in an evolutionary sense, and is responsible for such instinctive functions as smell, sexual response, and fear.

What emerges is a new view of politics as remarkably visceral and, to some extent, inherited, which may limit the possibilities for agreement across the classic divides – red state vs. blue state, conservative vs. liberal. When we debate issues, in other words, we do not so much argue a political position as assert who we are.

“Those who want an end to political bickering will have to come to terms with the fact that being conservative or being liberal is often genetically based and therefore unlikely to be jawboned or reformed away,” said John Alford, a Rice University political scientist who is involved in the new field.

As political physiologists study how political ideology works at its most basic level, they find that liberals and conservatives experience the world differently. Conservatives are more easily startled by threats, and when performing a habitual task they have more difficulty switching to a new response. Liberals, on the other hand, react less vigorously to threatening stimuli, and in performing a habitual task they are quicker to provide a new response.

“There is a seeming disjuncture between the popular belief that conservatives are strong and rational, and liberals are more touchy-feely – and increasing physiological evidence that the reverse may actually be true,” said Rose McDermott, a Stanford University political scientist.

Scholarly analysis of political ideology ignored biology until recently. From Aristotle onward, philosophers analyzed political behavior and other aspects of human nature from the outside, without venturing inside the functioning brain. Eighteenth-century Enlightenment thinkers propounded models of society in which people make thoughtful decisions about how government should be run.

In the 20th century, scholars began to explore the influence of culture, economic status, and other environmental factors on the development of political opinions. Yet these approaches stopped short of including biology, in part because the tools (such as brain scans) were not available, said John Hibbing, a political scientist at the University of Nebraska.

Hibbing, a leading figure in the new field, said a turning point was a Rice University study of identical and fraternal twins, published three years ago in the American Political Science Review. Using data from a large-scale study of thousands of sets of twins, researchers discovered that identical twins are far more likely than fraternal twins to share political attitudes on busing, foreign aid, school prayer, gay rights, pacifism, nuclear power, and many other issues. “Political and social attitudes” are “40-50 percent heritable,” the study reported.

“Political orientations such as liberalism and conservatism,” the study concluded, have “a significant genetic component.”

John Alford, one of the study’s authors, said that these genetic study results, along with his reading of Harvard psychologist Steven Pinker’s “The Blank Slate,” persuaded him and other scholars to embark on a quest to uncover the physical correlates of political ideology. Pinker’s book argues against the popular conception of the brain as a blank slate, which in his view skews research across disciplines, in favor of the notion that the brain possesses innate qualities that influence individual experience and opinions.

“To what degree are we political scientists guilty of implicitly assuming that the human brain is a blank slate?” Alford recalls wondering. Does political ideology have roots in biology? Could genes predict how someone might vote?

The next step for the young field was to look for ways that genetics and biology might affect social and political opinions. “We needed to find an actual path from genetics to how people feel about political issues of the day,” Hibbing said, “and then to see what physical systems are involved in these feelings about politics…”

After examining 46 such subjects, researchers found a strong correlation between subjects’ political attitudes and their physiological responses to threat. People who showed more “blink startle” and perspiration after a threatening stimulus tended to cluster on the right politically. They advocated capital punishment, school prayer, and defense spending, and they supported the Iraq war.

In contrast, liberals – who supported “less protectionist” policies such as gun control, open immigration, and increased foreign aid – showed significantly less physical response to the threatening stimuli. While education had some effect on the results, subjects’ blink and skin-conductance responses were much better predictors of their political attitudes. And the degree to which a person was startled by threatening stimuli indicated how much he or she advocated policies that protect society from external and internal threats such as wars and crime.

Our inborn response to threat underlies our political ideology, the study suggests. The researchers’ political questionnaire was limited to issues they could track along a spectrum of threats – that is, “whether or not something is perceived as corrosive of the social order,” Hibbing explained. In this way, support of school prayer, “biblical truth,” “patriotism,” and defense spending was more protectionist, whereas support for abortion, open immigration, gun control, foreign aid, pacifism, abortion, and same-sex marriage was less protectionist.

When researchers compared subjects’ physical responses with their political opinions, they found a striking correlation. “It was clear,” Hibbing said, “that some individuals have certain central-nervous-system reactions in the part of the brain involved in fear – there’s a genetic basis for this – and this brain activity underlies both their startle response and their political views…”

These studies mark the beginning of an effort to define brain functions and map brain regions that are involved in political attitudes. “Conservatives show more structured and persistent cognitive styles,” Amodio’s Nature Neuroscience study concluded, “whereas liberals are more responsive to informational complexity, ambiguity, and novelty.”

Based on these two studies, then, conservatives are more sensitive to threats than liberals, and liberals are more responsive to new cues.

Ultimately, biological differences between people with divergent political views may turn on “something deeper” than the conventional liberal-conservative axis, said Nebraska’s Smith. Lacking further data, it’s hard to put into words. “It may be that some people are more ‘traditionalistic’ – they like stronger leadership, stick with convictions, and believe rule breakers should be punished, not forgiven or rehabilitated – whereas other people are more open to ‘out’ groups and new ideas. These fundamental orientations are found across cultures.”

Indeed, the finding that people who feel strongly about politics cluster at two ideological extremes may suggest that our two-party system has a biological basis, said Hibbing.

“This broad left-right orientation pervades American politics and exists across the world and across time,” he said. He speculated that “25 to 30 percent” of the population at large falls into each camp, liberal and conservative, leaving slightly less than half of the population in the middle. These are the independents, or swing voters, who influence close races.

Simply knowing that our political preferences have physiological sources “may make us a little more humble, a little less quick to say, ‘My opponent is simply stupid,’ ” Hibbing said.

In fact, viewed through the long lens of evolutionary time, it would seem that the two camps depend on each other. A person who’s hard-wired to protect himself from danger may be able to avoid getting eaten by an attacking tiger – while his neighbor, who’s hard-wired to adapt to change, may sense an impending Ice Age in time to escape.

This is the reassuring note offered by political physiology at the end of another long, divisive American presidential campaign.

“The biological variation between liberals and conservatives is itself adaptive,” Alford said. “As loath as the two groups are to admit it, the checks and balances provided by the presence of the other orientation may make society stronger.”