Political science theory has long held that one's childhood and experiences influence how they think about politics.

But DNA, surprisingly, may play a critical role in how people broadly approach politics, from war and freedom to equality.

"Those who have studied political attitudes have missed half of the equation for far too long," University of Nebraska political scientist John Hibbing told about 75 people at a Feb. 8 lecture in Shields Library. Spon-sored by the Institute of Governmental Affairs, Hibbing's talk, "Beyond Heritability: The Physiological Differences between Liberals and Conservatives," echoed the classic 'nature or nurture' debate on the roles of heredity and environment in human development.

Instinctive responses

As Hibbing explained, geneticists who study behavior and personality have known for 30 years that genes play a large role in people's instinctive emotional responses to certain issues, their social temperament. Hibbing and his fellow researchers take that one step further, suggesting that genes prime people to respond cautiously — conservatively — or openly — liberally — to political issues.

The difficulty is that humans are not lab animals, he noted. "Studying predispositions would be easier if we were studying animals instead of humans," as scientists control environmental influences in lab research.

As a result, he and his colleagues based their research on examining the political attitudes, genes and DNA of identical and fraternal twins. Hibbing and the others found that identical twins, who share an entire genetic code, tended to answer the same on political issues more often than the fraternal twins, who are no more genetically related than siblings.

To define one as conservative or liberal, the researchers selected 28 questions most relevant to political behavior. In this view, conservatives tend to be more sensitive to threats from outside groups and will opt for greater punishment for those who deviate from the "in" group, which is reflected in their support of a strong military and capital punishment.

On the other hand, liberals are not as sensitive to threats from the outside and are more open to deviation within the "in" group — as a result, they are more tolerant of homosexuals and less inclined to back capital punishment.

Hibbing pointed out that a gene alone does not force one to take a specific stand on an issue — like either supporting or condemning the death penalty. Rather, a gene influences how one might broadly see those issues. For example, an absolutist — a person who has a strong perception of right and wrong — might be more inclined to favor the death penalty whereas a contextualist — one who sees more nuance in life — might be less so.

'Different ways'

When Hibbing's research appeared in 2005, it earned placement in the profession's premier journal, The American Political Science Review, and in-depth coverage by The New York Times, FOX News and MSNBC, among other media outlets.

In the big picture, Hibbing believes, this type of research has serious implications. If people took into account that their political opponents were "wired" a certain way, he said, they might be more tolerant of those differences and therefore less prone to unnecessary conflict.

"If we end up blowing up this planet, it's going to be over whether we have different ways of looking at political things, not whether we're introverted or extraverted. We can't deny our differences," said Hibbing.

Walt Stone, professor and chair of the UC Davis political science department, asked Hibbing what is the most "persuasive line of criticism" against his work?

Hibbing replied that "so many things affect the way genes are expressed," and some argue that the environment — not genes — ultimately shape political attitudes. He said he understands why some people are skeptical, though he is a bit frustrated with simplistic understandings.

"Genetics is not deterministic, but rather probabilistic," said Hibbing, adding "I don't know what it is about genes that short circuits people's abilities to think probabilistic." He readily acknowledges that individual variation does exist and that the environment does influence how genes are expressed.

However, genes are important, too, "but we've pretty much ignored that," he said.

Environment, not genes?

Some scientists do not agree with Hibbing's theory. One is Evan Charney, an assistant professor of political science at Duke University who told FOX News in 2006 that, "The very idea that something like a political ideology could be heritable is incoherent." Charney maintained then that any similarities found in twins' political beliefs can be attributed to the environment, not genetics.

Hibbing's talk, replete with DNA sequencing slides and references to neurotransmitters, seemed more like a biology lecture than a political science one. In many ways, it was reflective of how genetic research is shaping the social sciences, said political science graduate student Caitlin Milazzo.

"It is unfamiliar territory for me," said Milazzo, who is studying comparative politics, "but it's in line where we're going" in the field. "You're seeing a lot more of the hard sciences" being applied to social sciences. As for Hibbing's main idea, "it makes sense to me."

For more UC Davis Institute of Governmental Affairs events, see www.iga.ucdavis.edu.