Beyond social expectations: norms, moral commitment, and rule compliance among vegetarians

Vegetarianism is becoming increasingly prevalent in western societies. However, many self-identified vegetarians and vegans occasionally consume animal-derived products. This inconsistency between identity and behaviour raises questions regarding how individuals interpret and adhere to dietary norms. Although previous research has explored the role of social norms in dietary transitions, little attention has been paid to norm compliance among self-identified vegetarians. This study addresses that gap by analysing the influence of social expectations and internal motivations on adherence to the vegetarian norm “Don’t eat animals.” To do so, I conducted a survey of 469 Spanish vegetarians and vegans, including an experimental vignette in which participants were randomly exposed to different types of normative information. The study also measured respondents’ moral commitment and normative beliefs about vegetarianism. The vignette experiment results showed no significant effect of normative cues on the participants' stated likelihood of breaking the rule. However, regression analyses revealed that beliefs about the appropriateness of norm violations and dietary restrictiveness (vegan vs. vegetarian) were significant predictors compliance. Moral commitment to diet was not a strong predictor of norm following, although it reached statistical significance in one model. Notably, having more vegetarian contacts was associated with a higher likelihood of norm violations, whereas time on the diet predicted greater adherence. These findings suggest that compliance with the vegetarian norm is driven more by internalised normative beliefs than by external social expectations. They support a rule-based rather than expectation-based view of norm adherence, challenging the effectiveness of brief normative nudges in contexts where identity and moral reasoning are already salient. This study contributes to theories of norm compliance by highlighting the motivational diversity in lifestyle-based normative practices.