Conference Agenda

We investigate the causal effect of comparative feedback, i.e., information indicating how an individual’s carbon footprint compares to others’, on costly mitigation efforts. In particular, we consider individuals’ beliefs about their relative carbon footprint (i.e. their positions in the national distribution) as a source of heterogeneity. Using a survey experiment with a nationally representative sample from Germany, we calculate respondents’ carbon footprints based on the most emitting activities and elicit their beliefs about their relative carbon footprint via an incentivized task. A randomly selected subset of respondents then receives comparative feedback. We measure the effect of comparative feedback on respondents’ mitigation efforts. Our results show that nearly two-thirds of the respondents are subject to optimistic bias, i.e., they underestimate their relative carbon footprints. Moreover, while we find no effect of comparative feedback on the full sample, its effects vary by respondents’ relative carbon footprints and the direction of the bias. Respondents for whom comparative feedback conveys a positive signal of their prosociality—because they learn that their relative carbon footprints are small, smaller than they believed, or both—reinforce their mitigation efforts. Instead, respondents for whom comparative feedback conveys a negative signal of their prosociality—because they learn that their relative carbon footprints are large, larger than they believed, or both—reduce their mitigation efforts or do not change them. These contrasting responses result in a “divergence from the mean”, deviating from the “regression towards the mean” that is typically observed in studies of social norms and pro-environmental behavior.