Individual Versus Group Interest Violation: Surprise as a Determinant of Argument Scrutiny and Persuasion

Previous studies based on an attributional analysis of persuasion have suggested that a source who takes an unexpected position is perceived as more trustworthy and accurate than one who argues for an expected position. As a result, message processing is decreased when expectancies are violated compared to when they are confirmed. The current research suggests that these findings are limited to cases in which the unexpected position violates individual self-interest. When a source's unexpected position violates individual self-interest, attributions of trustworthiness are enhanced, but when the unexpected position violates group interest, this does not occur (Experiment 1). Instead, a violation of group interest induces surprise (Experiment 1) and produces enhanced rather than reduced message processing (Experiment 2).