Activated Self-Concept as a Mechanism Underlying Prevention Message Effects

Recent theorizing has posited that messages influence behavior via currently activated self-concepts. This proposition was tested in the context of evaluating real-world anti-marijuana television ads. A pretest yielded two themes (autonomy and responsibility) with two exemplars each. It was hypothesized that any effects of themes on behavioral willingness to use marijuana would be mediated by accessibility of a nonuser self-concept. An experiment was conducted in which participants (N = 129) viewed one of three clips that 1) contained embedded ads about nonuse supporting autonomy; 2) contained embedded ads about nonuse supporting responsibility to others; or 3) retained original commercials (control). Outcomes included reaction-time measures that assessed nonuser self-concept and willingness to use marijuana in social situations. Among those who identified as not a “druggie” and who were unwilling to smoke a joint at a party with friends, analyses revealed that exposure to the responsibility ads resulted in slower reaction times to endorse these positions, contrary to what might be expected from prevention messages. Among these participants, exposure effects on willingness were mediated by self-concept, as predicted.