Does it take a good argument to be persuaded? How manipulating quality of evidence affects message persuasiveness

Abstract

Two experiments investigated the effects of manipulating quality of evidence that supports arguments on message persuasiveness. The evidence quality was systematically manipulated by violating one or two of the relevant normative criteria. In experiment one, participants were presented with arguments embedded within a persuasive message. All supportive evidence was of either high, medium or low quality (between-subjects design). In experiment two, each argument was presented separately and was supported with high, medium and low quality evidence (within-subjects design). The recipients were insensitive to manipulations of evidence quality in the first, but sensitive to it in the second experiment. The findings are discussed with reference to conceptual and methodological issues in the study of attitude change.