Two faces of message repetition: audience favorability as a determinant of the explanatory capacities of processing fluency and message fatigue

This study offers a critical test of two competing theoretical accounts of message repetition effects—processing fluency and message fatigue—which have yet to be examined together under a coherent framework. Furthermore, integrating research on metacognition and motivated processing, we propose audience favorability toward message advocacy as a crucial moderator in this dynamic. A repeated-exposure experiment (N = 845) involving five different messages about climate change mitigation was conducted. Multilevel moderated mediation analyses showed that audience favorability critically moderated the mediational effects of the two mechanisms: For favorable individuals, repeated exposure enhanced persuasion through increased fluency and decreased fatigue. In contrast, for unfavorable individuals, repeated exposure diminished persuasion via increased fatigue and decreased fluency. Collectively, this study demonstrates that message repetition does not have uniform effects on persuasion but rather its effects critically hinge on audience favorability and challenges the fundamental notion that fluency and fatigue necessarily increase with repetition.