How norms work: self-identification, attitude, and self-efficacy mediate the relation between descriptive social norms and vegetable intake.

BACKGROUND The current studies aim to show that descriptive social norms influence vegetable intake and to investigate three potentially underlying processes (self-identification, attitude, and self-efficacy). METHODS In two studies, descriptive social norms regarding vegetable intake were manipulated (majority vs. minority norm). Study 1 investigated both the relation between baseline vegetable intake and self-identification, attitude, and self-efficacy, as well as the effect of the norm manipulation on vegetable intake over a one-week period. Study 2 investigated potential mediation of the effect of the manipulation on vegetable intake intentions through self-identification, attitude, and self-efficacy. RESULTS Study 1 showed that the proposed mediators were related to a baseline measure of vegetable intake. Moreover, in participants identifying strongly with the norm referent group, majority norms led to higher vegetable consumption than minority norms. Study 2 showed that the direct effect of the social norm manipulation on vegetable intake intentions was partly mediated by self-identification, attitude, and self-efficacy. CONCLUSIONS These studies shed first light on processes underlying the effect of descriptive social norms on health behavior. A norm describing the behavior of a salient social group leads people to identify more with, have more positive attitudes toward, and feel more self-efficacious regarding that behavior.