Effectiveness and context dependency of social norm interventions: five field experiments on nudging pro-environmental and pro-social behavior.

Social norm interventions hold the potential to change people's behavior. Five field experiments (N = 1,163) examined the effects of a simple and easily realizable social norm nudge based on the social media format "Be like Bill." The nudge consisted of a stick figure named Toni that communicated descriptive and injunctive norms regarding pro-environmental or pro-social behaviors. Nudge conditions were compared to no-intervention control conditions. Experiment 1 (N = 179) focused on paper towel consumption in a women's restroom at a German university. The nudge condition used less paper towels than the control condition, d = 0.48. Experiment 2 (N = 183) replicated this result (d = 0.32) in a more diverse setting of a women's restroom at a German Christmas market. Experiment 3 (N = 250) examined differences in the effects of prescriptive (i.e., 'do-norm') versus proscriptive (i.e., 'do not-norm') social norms on paper towel consumption again in a university women's restroom. The effectiveness of both social norm nudge conditions was shown in comparison to the control condition (d = 0.46; d = 0.40), while the prescriptive and proscriptive social norm manipulations did not differ. Experiment 4 (N = 206) applied the nudging approach to the use of plastic lids in a coffee shop, where no effect was found. Finally, Experiment 5 (N = 345) focused on the pro-social behavior of mask wearing in a bakery toward the end of the Covid-19 pandemic restrictions in Germany. In the nudge condition, more visitors put on face masks compared to the control group, d = 0.39. Limitations and contextual factors regarding the applicability of our social norm nudge are discussed.

Distinguishing fast change in social norms and slow change in personal norms in cooperative decision-making.

Psychological research on norms has shown that norms are highly relevant for individuals' decision-making. Yet, there is so far little understanding of how norms change over time. Knowledge about how norms change may help better understanding their potential for as well as limitations in guiding decision-making and changing behavior. The present work investigated change in individuals' cooperation norms. As an indicator of different underlying processes of norm change, the temporal dynamics of different types of norms were examined. It was assumed that participants' social norms are adapted quickly whenever the social situation changes, while personal norms change more slowly and gradually, abstracting part of the situational learning in interaction with one's personality. In an experimental study, participants played a repeated prisoner's dilemma game with artificial co-players representing a predominantly cooperative or uncooperative social setting, depending on the experimental condition. The condition was expected to affect slow learning of personal norms. Additionally, the cooperativeness of the social setting was varied repeatedly within conditions, expected to result in fast changes in social norms. Participants' personal and social norms were assessed throughout the game. As predicted, the temporal dynamics differed between norms with social norms changing quickly and personal norms more slowly. Personal norms strongly predicted behavioral decision-making and were predicted by situational and personality factors. Potential qualitative differences of the underlying norm change processes are discussed.