Young adults' social drinking as explained by an augmented theory of planned behaviour: the roles of prototypes, willingness, and gender.

OBJECTIVE: This study focused on young adults' alcohol consumption in social contexts. A dual-process model (including reasoned action and social reaction) was applied by combining the theory of planned behaviour (TPB) and the prototype/willingness model. A key question was whether willingness and actor and abstainer prototype variables would augment the TPB by increasing explained variance.

DESIGN: Participants completed questionnaires prior to spending an evening socializing over the weekend (Time 1). Behavioural data were obtained by telephone interviews a few days after the social drinking occasion (Time 2).

METHOD: N=300 people (mean age 25 years) took part in the study. The outcome measure of pure alcohol in grams was calculated based on participants' reports about their consumed drinks. Multigroup path analyses were conducted because of sex differences on behavioural and psychological variables.

RESULTS: The TPB explained 35% of the variance in men's and 41% in women's alcohol consumption. Augmentation with prototype perception and willingness contributed significantly to the prediction of intention (DeltaR(2)=.07) and alcohol consumption for men (DeltaR(2)=.14). A significant interaction implied that willingness led to heavy drinking particularly among those men who made negative evaluations of the abstainer prototype.

CONCLUSION: Women's alcohol consumption is explained by TPB variables via a more controlled reasoned-action path only, whereas additional processes (e.g., pursuing the actor image intentionally, rejecting the abstainer image more intuitively) are important for men. The moderating role of gender is discussed in light of traditional gender roles and recent trends in alcohol consumption.