People with extreme political views are most likely to think their beliefs are better than everyone else's, a new study shows.

As the government shutdown drags on, the new finding adds to a growing understanding about how basic psychological phenomena can contribute to the passions people often develop for their opinions. When those opinion-holders are politicians, consequences can be disastrous.

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“My guess is that people feeling superior about their beliefs is part of what’s going on in Congress,” said Kaitlin Toner, a social psychologist now at Vanderbilt University in Nashville, who worked on the new study while at Duke University in Durham, N.C.

“If you feel superior about what you believe, there’s little reason to compromise,” she said. “If you think you’re right and everyone else is wrong, it would be hard to come to a middle ground.”

During the 2012 elections, Toner became interested in what drove pundits and politicians to feel so sure about their views, regardless of which side of the aisle they were on. Not everyone could be right all the time, she figured. So what made people from diverse standpoints believe unwaveringly that their ideas were the best ones?

Plenty of previous research has focused on dogmatism, or ideological inflexibility, and study after study has shown that conservatives tend to be the most rigid and unwilling to change their views.

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Toner and colleagues chose instead to look at the sense of superiority, which can apply to people’s beliefs about everything from environmental issues to the use of cell phones in public and even whether Coke or Pepsi is the better soda. In all of these cases, Toner has found, people often think their views are both right and better than those of people who disagree.

To see how superiority might apply to politics, the researchers used online surveys to assess the beliefs of more than 500 people about nine controversial issues, including affirmative action, illegal immigration, voter identification and the government’s role in health care.

On a four or five-point scale, participants rated how conservative or liberal their views were on each topic. They also ranked how correct their beliefs were compared to other people's and they answered questions that assessed their level of dogmatism.

Consistent with earlier studies, people with more conservative views were more dogmatic and rigid. But when it came to superiority, the researchers reported in the journal Psychological Science, it didn’t matter if views were liberal or conservative.

A tourist takes cover underneath an umbrella while snapping a photo of the U.S. Capitol as snow and rain falls March 6, 2013, in Washington, DC.Chip Somodevilla/Getty Images

As long as their beliefs were on either extreme end, people felt strongly that their views were the best. People with moderate opinions did not feel as strongly that being moderate was superior to taking an extreme position.

The new study adds a nuanced perspective on why political extremists often refuse to change their positions on issues, said Philip Fernbach, a cognitive scientist and consumer researcher at the University of Colorado, Boulder’s Leeds School of Business.

There are at least a dozen psychological processes that push people toward extreme positions, Fernbach said, including something called confirmation bias, which describes the way people tend to seek out evidence to support the views they already hold. It is likewise common for people to surround themselves with likeminded peers who strengthen each others’ beliefs.

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In one of his own studies, published recently in Psychological Science, Fernbach also found that people tend to think they understand issues better than they actually do, a phenomenon known as the illusion of explanatory depth. When challenged to explain how policies work, people backed off from extreme opinions on those policies and became more moderate about them, probably because they realized that they knew less than they thought they did.

People exhibit the same kind of overconfidence in how everyday objects work, the team wrote, until they try to explain the mechanics of a toilet or combination lock and realize their understanding is fuzzier than they thought.

When it comes to politics, Fernbach said, a combination of factors contributes to impasses like the current gridlock in Washington. Politicians may be swayed by members of their party, who take extreme positions on issues they mistakenly think they understand.

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Perhaps one way out is to encourage everyone to become better informed and more thoughtful about why they believe what they do.

“On both sides, we have to open our eyes a little about the fact that all of us are guilty about these things,” Fernbach said. “In my own political life, I make an effort to be more thoughtful about claims from the side I support.”

“These issues are complex, and there is no simple solution,” he added. “It is a super-difficult puzzle about how we can begin to fix this situation.”