The Limits of Nudging: Can Descriptive Social Norms Be Used to Reduce Meat Consumption? It seems that nudging was a total failure.

Brachem, Johannes, Henry Krüdewagen, and York Hagmayer. 2019. “The Limits of Nudging: Can Descriptive Social Norms Be Used to Reduce Meat Consumption? It's Probably Not That Easy.” PsyArXiv. September 19. doi:10.31234/osf.io/xk58q

Abstract: A high level of meat consumption is associated with high emissions of greenhouse gases (GHG) and significantly contributes to anthropogenic climate change. One promising approach to reduce meat consumption without restrictions to freedom of choice might be the use of descriptive social norms as nudging interventions. We report two preregistered, randomized experiments (N1 = 450 and N2 = 899) in which we investigated whether written displays of true descriptive social norms about the rising popularity of vegetarian and vegan meals can be used to effectively nudge people towards more sustainable food choices, i.e. reduced meat consumption. Additionally, the main effect of subjects’ environmental attitude and a possible interaction of the social norms intervention and environmental attitude were examined. Participants were asked to choose one of five meals in 29 (Exp. 1) and 28 (Exp. 2) trials, resulting in a total of 38,222 observations. Subjects with a higher environmental attitude were more likely to choose meat-free meals, OR1 = 3.50, [2.84, 4.32]; OR2 = 2.79, [2.40, 3.23]. The results of both experiments showed no significant effect of the social norms intervention on subjects’ likelihood to select meat-free meals, OR1 = 0.73, 95% CI [0.49, 1.09]; OR2 = 0.97, [0.81, 1.16], and no interaction of the intervention with environmental attitude. An exploratory analysis suggested that subjects chose more meat-free meals if those made up a bigger portion of the offer. The results are discussed with regard to possible explanations, including a potentially high context-dependency of the efficacy of social norms interventions. The data, materials and preregistrations are available from https://osf.io/ruyfs/.