The effects of integrating instrumental and affective arguments in rhetorical and testimonial health messages

Recent research highlights the superior influence of affect over cognition in health decision making. The present study examined the independent and combined effects of 2 message characteristics that are thought to tap into the cognition-affect distinction: message format (rhetorical vs. testimonial) and argument type (instrumental vs. affective). In this 2 × 2 experiment, 81 college students were randomly assigned to 1 of 4 health messages discouraging binge drinking. The results indicated that messages containing affective arguments were judged more positively and perceived as more effective than were messages containing instrumental arguments. The results further revealed an interaction effect between message format and argument type. Testimonials were more persuasive when they contained affective arguments than when they contained instrumental arguments. Type of arguments did not influence the efficacy of rhetorical messages. Mediation analyses revealed that instrumental arguments reduce the efficacy of testimonials because they prevent individuals from being transported into the story, and increase psychological reactance. In conclusion, testimonial messages more effectively discourage binge drinking among college students when they contain affective, as opposed to instrumental, arguments.