Longitudinal associations between descriptive and injunctive norms on college drinking.

Perceived norms of drinking prevalence (descriptive norms) and approval (injunctive norms) are among the most robust predictors of college student drinking, but the dynamic fluctuations of these relationships over time are less understood. We examined longitudinal associations of descriptive and injunctive norms on alcohol consumption, disaggregating within-person fluctuations from between-person associations. Participants were 593 heavy drinking college students who completed measures of perceived descriptive and injunctive norms and drinking at baseline, one month, three months, six months, and 12 months. Longitudinal multilevel model analyses revealed that, at the between-person level, only descriptive norms predicted drinking. In contrast, both descriptive and injunctive norms at the within-person level predicted weekly drinking. The findings are the first to examine between- and within-person effects of descriptive and injunctive norms simultaneously on drinking and suggest that future college drinking interventions using normative influence would benefit from recognizing and incorporating within-person fluctuations in perceived norms.