(Newsroom America) -- A new nationwide study suggests why heavy users of partisan media outlets are more likely than others to hold political misperceptions.
It's not because the people using these sites are unaware that experts have weighed in on the issues. And using ideologically driven news only sometimes promotes misunderstanding of what the evidence says.
"Partisan online media drive a wedge between evidence and beliefs," said R. Kelly Garrett, lead author of the study and professor of communication at The Ohio State University.
"The more people use these sources, they more likely they are to embrace false claims, regardless of what they know about the evidence."
Partisan media have effects on both Democrats and Republicans, the researchers found.
Strikingly, use of partisan media contributed to misperceptions above and beyond the influence of partisanship itself.
"What you believe isn't just about what party you belong to. Where you get your news matters, too," Garrett said.
Garrett conducted the study with two former graduate students: Brian Weeks, now with the University of Michigan, and Rachel Neo, now with the University of Hawaii at Manoa.
Garrett said that the study's focus on changes in media use and political beliefs over time gives the researchers a unique opportunity to understand how these two factors influence one another.
Data came from a three-wave panel study conducted during the 2012 presidential election. Participants were interviewed first during July-August 2012, a second time in August-October and a final time in November. A total of 652 nationally representative participants completed all three surveys.
All participants were asked about their knowledge of and beliefs about four different issues in the campaign, two of which favored Republicans and two that favored Democrats.
The well-documented falsehoods favored by Republicans were the claims that President Obama was not born in the United States and that there were weapons of mass destruction in Iraq.
The Democrat-favored misperceptions were that Mitt Romney actively managed Bain Capital when the firm started investing in companies that outsourced work abroad, and that there was an immediate drop in marine life diversity in the Gulf of Mexico following the BP oil spill.
The researchers measured how often participants visited websites characterized as favoring liberal positions, including the New York Times, MSNBC, Huffington Post, ThinkProgress and Daily Kos; and those favoring conservative positions, such as the Wall Street Journal, FOX News, Drudge Report, TownHall and Cybercast News Service.
One explanation for why partisan media encourage misperceptions is that their users are sheltered from the truth. For example, it is sometimes suggested that viewers build their own "echo chambers" where they never hear facts that contradict what they believe. But there is no evidence of that in this study, Garrett said.
"In fact, we found modest evidence that the opposite sometimes occurs - people who were heavy users of ideological news sites were more likely to say they'd heard evidence related to one of the issues," he said.
For example, the inaccurate claim about Romney's role at Bain Capital would have benefited the Democratic presidential candidate if it was true, yet a typical citizen who did not use liberal sites had a 47 percent chance of being "unsure" what fact checkers had concluded. A heavy user of liberal sites had only an 18 percent chance of being unsure of the facts.
Another possibility is that partisan news sites could undermine accurate knowledge by giving their audience false impressions of the evidence. For example, heavy users of partisan media may not know what knowledgeable people in the media say about the truthfulness of a particular belief.
When researchers tested this possibility, the results were more mixed, Garrett said. Still, there was evidence that this was not the best explanation of what was happening.
The strongest and most consistently supported explanation of how partisan online media promote misperceptions was that their use leads viewers to reach conclusions favored by the partisan source, despite whatever else the viewers might know, Garrett said.
For example, a Republican who knows the facts but does not go to conservative news sites has only a 3 percent chance of incorrectly answering questions about Obama's birthplace or weapons of mass destruction. An otherwise identical heavy user of conservative sites has an almost one-in-three chance (31 and 33 percent respectively) of holding a misperception.
Similarly, a Democrat familiar with fact checkers' conclusions about Romney who does not visit liberal sites has only a 3 percent chance of answering incorrectly. But a heavy user of liberal sites has a 10 percent chance of answering incorrectly, contrary to their knowledge of the evidence.
Because the researchers looked at participants over time, they were also able to see a feedback loop: Use of partisan media leads to inaccurate beliefs which lead to more partisan media use and so on, Garrett said.
"It isn't just that people who hold false beliefs are more likely to consume partisan media," he said. "The use of these outlets also predicts false beliefs in the future."
The results suggest that we can't fix the problem of political misperceptions by education alone.
"People who believe falsehoods often know the evidence, but understand it differently, in part because of the way it is presented to them in the partisan media," Garrett said.
"It is a crisis of critical thinking. Examining the evidence for ourselves too often means allowing our own biases to influence how we evaluate claims. And ideological news sources encourage us to do that."