Party Bias in Political-Advertising Processing--Results from an Experiment Involving the 1998 Taipei Mayoral Election

This study employed an experiment during the official campaign period to investigate the impacts of political advertising in the 1998 Taipei mayoral election. Specifically, this study argues that voters' party identifications have a moderating impact on how they respond to advertising messages. As expected, partisans evaluated political advertising sponsored by candidates of their affiliated party as more persuasive and likable than political advertising sponsored by candidates of the competing party. Independents showed no different responses to the ads by the two competing candidates, however. In addition, partisans who were exposed to either positive ad messages or negative ad messages for two competing candidates, compared with those who were exposed to no ad messages, had a significant positive change in voting support for the candidate nominated by their affiliated party, but a significant negative change in their voting support for the candidate of the opposing party. In clear contrast to partisans, independents' voting support for candidates was not influenced by advertising exposure. Contrary to expectations, the results also showed that affiliated voters' evaluations of the candidates they supported deteriorated after exposure to advertising messages, whether positive or negative. Explanations and implications for these findings will be discussed.