Social norms and climate-friendly behavior of adolescents

about the behavior of others influences adolescents’ perception of social norms and subsequent decision-making. Social norms as a determinant of (pro-environmental) behavior A growing body of experimental research examining the role of social norms in adult behavior has shown that information about others’ behavior can alter individual decision-making, both in general [41–44] and in the pro-environmental domain [7, 29, 45, 46]. Learning about the behavior of others allows individuals to draw inferences about the predominant social norm. Yet, the existing literature shows that receiving this information either by observation or via social norm nudges does not always lead to (the desired) behavioral change [32, 44, 47]. Thus far, three factors have been identified in the literature to determine the effectiveness of social norm interventions. First, and perhaps obvious, individuals need to notice the new informa- tion, so the salience of the information is key for its influence [29]. Second, social similarity has been shown to determine the extent to which individuals are influenced by information about other people’s behavior. The more similarities the individual shares with the reference group, the more relevant the information about their behavior becomes and the stronger its influence [41, 46, 48, 49]. Third, social norms are based on two relevant beliefs: (a) empirical expectations, or what behavior the individual believes that others engage in, and (b) normative expectations, whether the individual believes the behavior is considered by sufficiently many

others to be socially appropriate [8, 50]. Please note, some other authors distinguish between descriptive norms (i.e., what people in a group normally do) and injunctive norms (i.e., what people in a group deem to be appropriate behavior; e.g., [29, 51]). For the empirical work in this study, we chose to work with Bicchieri’s concept [8], as it clearly defines that the behav- ioral influence stems from social expectations. The strongest influence of social norms on behavior is observed when both expectations coincide. When empirical and normative expectations are non-congruent, on the other hand, people tend to follow the empirical expectation, particularly when the observed behavior is in line with self-regarding preferences [41, 43]. Some studies suggest that observing others’ behavior may also update one’s normative expectations [44, 51]. However, this link is less established. Participants in the aforementioned studies were adults, often university students. Little is known about the validity of the studies’ findings for other socio-demographic groups. In our study, we analyze whether and how 628 adolescents between 11 and 17 years of age change their empirical expectations, normative expectations, and, lastly, climate-friendly behavior in response to information they received about the behavior of relevant others. As a reference group, we chose peers with a high degree of socio-economic similarity (i.e., same age, same school type, and from the same city). Depending on the randomized treatment manipulation,

participants received information that those relevant others donated either low or high amounts of their compensation for participation in the study to a CO2 offsetting scheme. In the next sections, we describe our experimental design, hypotheses, and sample charac- teristics, followed by the experimental results section, before concluding with a discussion and avenues for future research. Experiment and hypotheses The study was conducted in January 2020 at two high schools in Osnabru¨ck, Germany with students from Grades 8, 9, and 10, who are typically between 13 and 16 years of age. Our approach of bringing the lab into schools has been successfully employed to probe the validity of findings from adult samples with regard to, for example, the rationality, risk, time, and PLOS ONE Social norms and climate-friendly behavior of adolescents PLOS ONE | https://doi.org/10.1371/journal.pone.0266847 April 27, 2022 3 / 16