Social norms and climate-friendly behavior of adolescents

(LOW vs. HYPO LOW: p = 0.015). For the normative expectations, we find the reverse effect. When students were presented with small hypothetical donation amounts (HYPO LOW), they rated small and medium donation amounts as more socially appropriate. This was the case not only when compared to CONTROL, where no such information was available (p <0.01, CI: [0.220, 0.719] and p <0.05, CI: [0.023, 0.497], respectively), but also in comparison to the nor- mative expectations in LOW, where the same amounts were presented but resembled donation decisions of peers (LOW vs. HYPO LOW: p = 0.041). We interpret this stronger shift as an indication for a more pronounced demand effect when reference donation amounts were hypothetical, we will come back to this point in the discussion. For the realized behavior, we find that the two HYPO conditions, HYPO LOW and HYPO HIGH, like their counterparts LOW and HIGH, do not unfold a significant effect on the giving decision. In summary, this means across all specifications we only find support for one of our predicted treatment effects: LOW decreases the empirical expectations relative to CONTROL and HIGH (H1.2 and H1.3). Age-specific analysis To evaluate whether the influence of information about peers’ behavior is the same across all age groups, we performed an age-specific analysis by splitting the sample by grade. Fig 3 plots Fig 3. Grade-specific coefficient plots of regression models estimating the treatment effects. This figure presents

the tobit regression coefficients and estimated 95% confidence intervals. The coefficient interpretation is that if a student in Grade 8, 9, or 10 was part of either the HIGH or LOW treatment, their donation amount is expected to change by the respective regression coefficient in the censored tobit scale, holding everything else constant. Full model results are reported in Section B.5 in S1 File. Additional controls were gender, age, migration background, students’ connectedness to nature (Inclusion with Nature Scale [58], existing engagement in climate-friendly behaviors, and participation on Fridays for Future protests. The models also include fixed effects on school class level. https://doi.org/10.1371/journal.pone.0266847.g003 PLOS ONE Social norms and climate-friendly behavior of adolescents PLOS ONE | https://doi.org/10.1371/journal.pone.0266847 April 27, 2022 10 / 16