This means that the first ideas you develop about a candidate will influence your vote more than those you learn later. For candidates, this means that advertising early in the campaign probably has a bigger positive impact than later ads. Voters start with positive attitudes toward unknown candidates. Most researchers have assumed that people are neutral toward candidates in the beginning, but this study showed that voters have a slightly positive attitude even before they know anything about those who are running, Krosnick said. Candidates can take advantage of the fact that they start the campaign on the positive side with most potential voters.
Negative information has more impact on voters than positive information.
This helps explain why negative campaign ads are so effective. Less knowledgeable voters make their decisions in much the same way as do informed voters. You don't need special expertise in politics to make a voting decision. Co-authors of the study were Allyson Holbrook of Ohio State, Penny Visser of Princeton University, Wendi Gardner of Northwestern University, and John Cacioppo of the University of Chicago. The research was conducted partly while Krosnick was a Fellow at the Center for Advanced Study in the Behavioral Sciences and supported by a National Science Foundation grant.