Abstract
Two problems, one data-driven one theory driven limit the study of campaign effects.
First, it is difficult to separate who voters chose and why from who they would have chosen and
why they made that choice had there been no campaign. This is the relevant comparison and
most data are simply inappropriate for answering this question because they do not observe how
an individual behaved without the campaign. Second, even though we know that campaign
effects stem from both persuasion (changing the content of a voter’s attitude ) and heresthetic
change or priming (changing the weights applied to or salience of specific determinants of vote
choice), there have been nearly no attempts to undercover the underlying psychological
mechanisms that lead voters to change which determinants they rely on. In this paper I draw on
the recent controversy surrounding the different forms of attitude strength (Miller and Peterson
2004), to suggest that changes in citizens’ uncertainty are the key mediator of campaign effects.
The results suggest that persuasion and changes in uncertainty but not ambivalence or
importance are responsible for the changes in voters’ decisions during the campaign.
2
Convention