Much of the negativity is being driven by the individual campaigns and dialogue on social media. (Courtesy Creative Commons/ Nick Jugular)

The study found that 71 percent of the personal assertions about Mitt Romney were negative, while a comparable 72 percent of assertions about Barack Obama were negative. The study analyzed the personal portrayal of a candidate in 50 major news outlets over a 10-week period and found this election to be the most negative since 2000, when Pew started monitoring campaign master narratives.

Media coverage of President Obama focused on his handling, or mishandling, of the economy. The most prevalent assertion is that Obama has not done enough to fix the economy, while the second most common assertion was that the economy would have been worse without his policies. Less consistent were claims that Obama does not believe in capitalism, individualism and that he lacks integrity. Some coverage was given to the notion that Obama was a foreign-born Muslim but the coverage protrayed it as a rumor or sideshow that had been discredited.

The prevailing master narratives about Romney focused on suspicions over his career at Bain Capital and perceptions that he is a wealthy elitist and an awkward campaigner. And while Romney has made the economy the central platform of his campaign, ten percent of coverage asserted that Romney's ideas would actually hurt the economy while eight percent of coverage found his economic plans too vague.

"It is just nastier than normal," said Rosenstiel, told the Guardian. The 2004 campaign was also negative but heavily influenced by external events like the Iraq and the Abu Ghraib prison scandal.

One reason for the personal, negative tone was that the campaigns and partisan activists, and not journalists, have been determining the narratives about the candidates. The study found that 48 percent of assertions came from partisan sources while journalists accounted for only 19 percent of assertions about the candidates. Outside experts accounted for 10 percent. The study concluded that journalists "to an increasing degree are ceding control of what the public learns in elections to partisan voices.”

Some media outlets fared better in terms of partisanship, however. From Forbes:

This shift takes several forms. On cable news, the most popular talk show hosts on Fox News and MSNBC are now more likely to feature a single guest, often a campaign surrogate or other reliably partisan mouthpiece, than they were in the past, when multi-guest panels were more the norm. (CNN, according to the authors, is out of phase with this trend and more closely resembles the major broadcast networks in its political coverage.)

The study concluded some news organizations have been acting as a conduit, rather than a filter for campaign talking points. From the Washington Post:

That finding might reflect several trends: the campaigns’ nearly instantaneous ability to respond to attacks; the highly polarized nature of the campaign; and shrinking resources among media organizations, which he said have emphasized breaking news over in-depth analysis.

Of the four presidential campaigns that the project has studied, the 2012 race is similar to 2004 in terms of being the most negative. In 2004, 75 percent of the media narratives about the Democratic challenger, Sen. John F. Kerry (Mass.), were negative, compared with 70 percent for President George W. Bush, according to the organization.

The project also noted that the negative tone of the 2012 coverage correlates with — the center declined to say “caused” — negative public attitudes toward the candidates, with both nominees viewed less favorably in public opinion polls than any major-party candidate since 1992.

The Obama campaign released a new campaign ad the same day as the Pew study was published. It features former President Bill Clinton warning voters that Romney will "go back to deregulation." President Clinton promoted deregulation in his own administration, signing the law which repealed the Glass-Steagall Act, the Depression-era law which separated commercial and investment banks. Clinton has since said the decision was a mistake.

[View the story "Just as you expected: negative media coverage dominates the campaigns." on Storify]

Follow Neon Tommy's coverage of the 2012 election.

Reach Executive Producer Dawn Megli here.