Negative Advertising and the Dynamics of Candidate Support

Scholars have spent a great deal of effort examining the effects of negative advertising on citizens' perceptions of candidates. Much of this work has used experimental designs and has produced mixed findings supporting one of two competing theories. First, negative ads may harm candidates who sponsor them because citizens tend to dislike negativity. Second, negativity may drive down citizens' support for the targeted candidate because the attacks give people reasons to reject the target. We argue that the mixed findings produced by prior research may be driven by a disregard for campaign dynamics. We present a critical test of these two theories using data drawn from 80 statewide elections-37 gubernatorial and 43 U.S. Senate contests-from three election years and public opinion polling collected during the last 12 weeks of each campaign. We find that a candidate's support declines as her advertising strategy includes a higher proportion of negative ads relative to her opponent and that this process unfolds slowly over the course of the campaign.