In the past, campaigns have been wary of deploying negative ads for fear of backlash, says [political scientist Travis] Ridout. However, that may be changing as campaign operatives see evidence that negative ads can break through party affiliations and also sway independent voters. A case in point: Mitt Romney’s February landslide in the Florida Republican primary came on the heels of the “most negative advertising campaign in history,” according to the nonprofit Campaign Media Analysis Group. The week before the primary, 99 percent of Romney’s ads were negative, while 95 percent of Newt Gingrich’s ads were negative.
“I wish candidates wouldn’t use them, but attack ads work perfectly,” says Joel Weinberger, PhD, a psychology professor at Adelphi University. “Democrats know it, Republicans know it, and it’s going to get ugly this year.”A few points here. First, I have a hard time believing that the Florida Republican primary was the "most negative advertising campaign in history," although I guess it depends on how we're defining our terms. History's pretty long. But more importantly, just because a lot of money was deployed by Mitt Romney and his allies against Newt Gingrich and Romney won hardly proves that Romney won because of the negative ads. It's possible -- John Sides has some tentative evidence suggesting that the ads mattered -- but we'd need a lot better data than we currently have to prove that negative ads swayed independent voters away from Gingrich and toward Romney.
And then there's Weinberger's sweeping conclusion that "attack ads work perfectly" and that everyone knows it. Yes, a lot of people are convinced that they work, but that's far from proof that they do. To cite Sides again, "We haven’t remotely arrived at a place where 'research' suggests that negative ads 'work.'" Quite a bit of research suggests they don't do much at all.