Social commentary about prevention messages may affect their likelihood
of acceptance. To investigate this possibility, student participants
(N = 663) viewed three anti-marijuana
advertisements, each followed immediately by videotaped discussions involving
four adults or four adolescents using either extreme or moderate language in
their positive commentaries. The commentaries were expected to affect
participants’ perceptions of the extent to which the ads were designed
to control their behavior (perceived control), which was hypothesized to inhibit
persuasion. Two indirect effects analyses were conducted. Marijuana attitudes
and usage intentions were the outcome variables. Both analyses revealed
statistically significant source by language interactions on
participants’ perceived control (both p < .02).
Further analyses revealed significant indirect effects of language extremity on
attitudes and intentions through perceived control with adult, but not peer
sources (both p < .05). These perceptions were
associated with more negative marijuana attitudes and diminished usage
intentions when adults used moderate (vs. extreme) language in their favorable
ad commentaries (both p < .05). The findings may
facilitate development of more effective prevention methods that emphasize the
importance the role of perceived control in persuasion, and the impact of
interpersonal communication variations on acceptance of media-transmitted
prevention messages.