Carbon labels are an increasingly popular policy tool to decrease the carbon footprint of consumers’ choices. However, not much is known about their effectiveness relative to other policy instruments and the channels via which they affect behavior. Through a series of experiments, including two framed field experiments (N = 289 and N = 444, respectively) and one natural field experiment (involving more than 120,000 purchase decisions by over 10,000 customers) conducted in a student canteen setting, I provide causal evidence that carbon labels impact consumption behavior. I evaluate the labels’ effectiveness in comparison to a carbon tax, both through direct elicitation (framed field experiment) and by using pricing variations (natural field experiment). In both settings, I find that the overall effectiveness of the labels is similar to that of a carbon tax of €120 per tonne. Further, complementary evidence from both settings conveys that the labels on average create psychological benefits for consumers. In the second framed field experiment, I identify the behavioral channels driving label effectiveness by varying treatment conditions. I find that carbon labels mainly impact consumers by directing attention towards carbon emissions, and less by correcting consumers’ perceptions about carbon footprints. Using a structural model and data from the second framed field experiment, I estimate that carbon labels on average increase consumer welfare.

We compare the behavior and welfare effects of two popular interventions for resource conservation. The first intervention is social comparison reports (SC), which primarily provides consumers with information motivating behavioral change. The second intervention is real-time feedback (RTF), which primarily provides consumers with information facilitating behavioral change. In a field experiment with around 1,000 participants, we directly observe the interventions’ effects on participants’ behavior. Further, we elicit participants’ willingness to pay for receiving the interventions, both before and after having experienced them for one month. We find that SC leads to a reduction in water use per shower by 9.4%, RTF by 28.8%, and the combination (BOTH) by 35.0%. Our willingness to pay results show that all interventions are highly valued by participants and that willingness to pay for RTF and BOTH is significantly higher than for SC. Furthermore, we find that the valuation of the interventions barely changes after a one-month experience. Our results suggest that while both interventions improve welfare, providing consumers with information facilitating behavioral change achieves a higher impact and a slightly higher welfare increase than providing consumers with information motivating behavioral change.

Press release: RWI

Media: FAZ | Energy Institute at Haas

Interventions to decrease meat consumption are often only implemented for short periods of time, and it is unclear how they might have lasting effects. We combine student canteen consumption (over 270,000 purchases made by over 4,500 guests) and survey data (N>800) to study how a one-month intervention to decrease meat consumption affects consumer behavior post-intervention. During the intervention period, meat meals were eliminated from the menu of the treatment canteen, while the two control canteens were unaffected. Using a difference-in-difference approach, we estimate that guests usually frequenting the treatment canteen did not significantly reduce their visits to the canteen during or after the intervention. In the two months following the intervention, they were still 4% less likely to choose the meat option when visiting the canteen, relative to baseline. A large part of this effect seems explicable with guests learning about the quality of the canteen’s vegetarian meals. We find little to no evidence of the intervention changing perceived social norms.

Press release: English | German

Media: SRF 4 | Deutschlandfunk Nova | WDR Cosmo | Rhein-Zeitung | General-Anzeiger Bonn | Bild der Wissenschaft | Aponet | Yumda

In a laboratory experiment, we study the effect of acute and chronic stress on individual risk-taking behavior. We exogenously induce acute stress using the Trier Social Stress Test for Groups developed by von Dawans, Kirschbaum, and Heinrichs (2011). We measure subjects' acute stress by their heart rate, saliva cortisol levels, and their chronic stress by their hair cortisol levels. We elicit the subjects' risk-taking tendency by using randomized lottery pairs. Employing a within-subject design, i.e., eliciting each subject's risk-taking propensity both with and without the exogeneous acute stress, we aim to shed light on individuals' heterogeneous responses to acute stress in terms of risk-taking. It thereby contributes to the inconclusive literature on the causal effect of acute stress on risk-taking.