Science Daily looks at a study from American Politics Research that finds ads sponsored by independent groups are much more likely to have an impact on voters than those coming from campaigns. This is significant because of the proliferation of super PACs spending on elections.
Researchers Deborah Jordan Brooks and Michael Murov showed negative ads about a ficticious candidate. The ads either came from the candidate's opponent, an independent group or had no endorsement.
Regardless of sponsorship, Brooks and Murov found that the ads were similarly persuasive regarding the flaws of the candidate who was the target of the ad. The difference was that public penalized a candidate for sponsoring such an ad with what is known as a "backlash" effect. Because there was far less backlash aimed towards the benefitting candidate if the ad sponsor was an independent group, the attack was far more effective when it was sponsored by Citizens for a Better State Government than by the candidate himself.
The authors also suggest that since there is reduced potential of backlash from voters, independent groups may face incentives to produce highly controversial advertisements while facing relatively few incentives to be truthful in ads.