The Roles of Identity- and Belief-Driven Motivated Reasoning and Source Credibility in Persuasion on Climate Change Policy

Developing effective messages to promote climate action requires an understanding of how these messages are processed by different groups. Though the influence of partisan identity on this processing is well established, much less is known about the role of preexisting climate beliefs. Furthermore, scholars have recently raised the possibility that what appear to be partisan effects on message judgments may simply be byproducts of accuracy-driven differences in perceived source credibility. Three online experiments revealed evidence that speaks to these conversations. The results show that message source, political affiliation, and preexisting climate beliefs combine nonadditively to affect persuasion. Furthermore, their effects are mediated by perceived source credibility. However, the evidence also suggests that this pattern emerged not because accuracy goals drive different perceptions of credibility but because credibility judgments are equally susceptible to directional motivated reasoning.