“One reason the campaign has been so negative is the skyrocketing involvement of interest groups, who have increased their activity by 1100 percent over four years ago” said Erika Franklin Fowler, co-director of the Wesleyan Media Project. “But we cannot attribute the negativity solely to outside groups. Even the candidates’ own campaigns have taken a dramatic negative turn.”

The study indicates that more than half (53%) of the ads put out by the various campaigns from the beginning of last year through April 22 have been negative, compared to just nine percent at this point in the 2008 election cycle. And 86% of the commercials put out by independent groups, such as super PACs, are negative, up from 25% four years ago.