Social impediments to meat-eaters’ adherence to critical calls for a meat-free diet: An experimental test of social norm and message source effects

Reducing meat consumption is highly effective for reducing personal carbon emissions, yet most people in Western nations still eat meat. We build on recent research highlighting that group boundaries may impede dietary change by (a) promoting pro-meat norms and (b) prohibiting critical calls for a veg* diet (vegetarian and vegan, i.e., meat-free). Past research relied on self-reports and behavioural measures of engagement, leaving open whether these effects extend to food consumption settings and ad-hoc meal choice. We conducted two pre-registered experiments in which meat-eaters read critical calls to adopt a veg* diet, either by a vegan (outgroup) or a meat-eater (ingroup). In Experiment 2, participants moreover read an article either highlighting a veg* or a meat-eating norm. We then assessed actual (Experiment 1) or hypothetical (Experiment 2) meal choice as dependent variables. As predicted, intergroup criticism (i.e., voiced by veg*s) consistently led to message rejection in comparison to the same criticism voiced by meat eaters, but we did not observe effects on meal choice. Norms neither had a main nor interaction effect on self-reports and behaviour. We discuss potential intermediary processes between engagement with and adoption of a vegan diet and derive evidence-based recommendations for constructive communication across group boundaries.