Is politician A or politician B more persuasive? recipients' source preference and the direction of biased message processing

Abstract

Participants' preference for one of two politicians running for the post of Chancellor in Germany was measured. Under conditions conducive to effortful processing, participants were then presented with a persuasive message ascribed to one of these two sources. The message was either unambiguous strong, unambiguous weak, or ambiguous. Different from previous research on the role of message ambiguity for attitude change, the ambiguous message consisted of arguments rated as moderately convincing in a pretest rather than of a mixture of strong and weak arguments. The results were in line with predictions derived from the heuristic-systematic model (HSM). Indicating unbiased systematic processing, an unambiguous strong message led to more agreement than an unambiguous weak message. In the case of an ambiguous message, in line with the HSM's bias hypothesis, more agreement was found among participants preferring the source politician as compared to participants preferring the other politician. Copyright © 2003 John Wiley & Sons, Ltd.