The role of audience favorability in processing (un)familiar messages: a heuristic-systematic model perspective.

Several mechanisms of processing (un)familiar messages-processing fluency, message fatigue, interest, and counterarguing-are documented but studied independently, preventing a holistic understanding of how we process (un)familiar messages. This research integrates these mechanisms under a coherent theoretical framework based on heuristic-systematic model and identifies which one becomes dominant as a joint function of message familiarity and audience favorability. Across two studies concerning social distancing (Study 1; N  =   412) and smoking (Study 2; N  =   300), message fatigue and counterarguing were heightened in unfavorable audiences processing familiar and unfamiliar messages, respectively. Interest was dominant among favorable audiences processing unfamiliar messages in Study 2. Processing fluency was not heightened under any conditions. In models testing mediational capacities of the four mechanisms simultaneously, message fatigue and interest were significant mediators of the effects of audience favorability and message familiarity on persuasion, respectively. This research underscores the importance of considering audience favorability when studying the effects of message familiarity.