It's All in the Name: Source Cue Ambiguity and the Persuasive Appeal of Campaign Ads

As strategies for campaign political advertising become more complex, there remains much to learn about how ad characteristics shape voter reactions to political messages. Drawing from existing literature on source credibility, we expect ad sponsorship will have meaningful effects on voter reactions to political advertisements. We test this by using an original experiment, where we expose a sample of student and non-student participants to equivalent ads and vary only the paid sponsor disclaimer at the end of the message. The only thing that differs across stimuli is whether a political candidate, a known interest group, or an unknown interest group sponsors the advertisement. Following exposure to one of these ads, participants complete a posttest battery of questions measuring the persuasiveness of the message, source credibility, and message legitimacy. We find that ads sponsored by unknown interest groups are more persuasive than those sponsored by candidates or known interest groups, and persuasion is mediated by perceived credibility of the source. We conclude by discussing our findings and their implications for our understanding of contemporary campaigns.