CHAMPAIGN, Ill. -- The media slant political news to the left or right to increase ratings and profits, spinning up an information vacuum that can lead to mistakes at the ballot box, a new study by three University of Illinois economists says.
Media bias has become increasingly profitable given a polarized electorate in which conservatives and liberals want news coverage that tilts toward their political leanings, according to the study by Dan Bernhardt, Stefan Krasa and Mattias Polborn.
"You listen to news not just to get informed, but to be entertained," Krasa said. "And you're more entertained if they tell you you're right than if they tell you you're wrong."
But even though voters typically take the spin into account rather than following blindly and that the media only slant news rather than falsifying it, selective reporting can still factor into mistakes at the polls, according to findings that will appear in the Journal of Public Economics.
Voters get an incomplete picture as conservative media outlets favor Republicans and blast Democrats, while liberal outlets do just the opposite, according to the study, "Partisan Polarization and the Electoral Effects of Media Bias."
"Biased media suppresses information that is unfavorable to 'their' candidate, and even smart voters cannot completely recover the truth from their reports," Polborn said.
The study says media bias can also trip up voters who try to account for the slant some outlets put on the news.
For instance, an independent voter who hears only minor negative news about a Democrat through a conservative outlet could rightly infer that the Democrat has no glaring faults or they would have been trumpeted. But the Republican's quality remains in question because the voter rationally expects any negative news would be stifled.
Bernhardt and Krasa say the earnings-driven bias that tailors news to give conservatives or liberals what they want to hear could weigh on this fall's presidential race. Conservative media outlets will tout Republican John McCain's strengths and downplay or ignore weaknesses, while Democrat Barack Obama will get similar kid-glove treatment from left-leaning media, the economics professors say.
"Selective reporting by a liberal or conservative outlet can cause voters to make mistakes because they don't hear the whole story," Bernhardt said. "If collectively enough of them make mistakes it can switch the winner of the election."
Media bias could play an even bigger role in this year's presidential race because Obama is still a relative unknown whose positions and past will be selectively reported as they surface during the campaign, Bernhardt said.
"There could be too little crossover voting by moderate Republicans because if Obama turns out to be good it won't be reported by the media they use," Bernhardt said. "If it turns out he's bad, there could be too little crossover voting by moderate liberals."
Krasa says the impact of slanted reporting would only be felt in swing states such as Florida, Ohio and Pennsylvania where moderate voters can sway an election.
"Media bias would not have a perceptible impact in non-swing states," Krasa said. "If a Democratic vote for McCain makes a difference in a blue state, like Illinois, he's going to win nearly every other state anyway, so it's irrelevant."
Opinion polls illustrate the ideological ties that media outlets such as alleged right-leaning Fox News or perceived liberally bent CNN use to expand their audience and, in turn, advertising revenues, according to the study.
A poll during the 2004 presidential campaign showed that among voters who get most election news from Fox, 70 percent supported President Bush, compared with 21 percent for Democratic rival John Kerry. The results were just the opposite among CNN viewers - 26 percent for Bush and 67 percent for Kerry.
The media's spin also influences views on seemingly factual matters, according to the study, citing a 2004 poll that showed 84 percent of Bush supporters thought Saddam Hussein had strong links to al Qaeda, compared with 37 percent of Kerry backers.
Krasa says averting bias-driven mistakes at the polls would require voters to seek out both sides, something most are unwilling to do because they don't think their vote will be pivotal.
"The problem is to avoid making mistakes you're asking voters to work harder, and it's not necessarily in their self-interest to do that," Bernhardt said. "So there's this paradox. Becoming better informed could potentially help everybody else because we would vote better and wouldn't make mistakes. But people don't internalize the consequences for everybody else, they only internalize their own. So they under invest in information. Most do."