[Working paper, 2026]

Abstract: The green transition faces multiple overlapping political economy challenges, with backlash against environmental policies driven both by economic concerns and politicization of climate change. We study how economic reasoning as well as social and psychological factors jointly shape public acceptance of carbon taxation (with uniform redistribution). Using a pre-registered survey experiment in the U.S. (N = 2, 688), we show that factual policy explanation and social norm-based video messages each increase short-run policy acceptance, but this does not translate into higher average environmental donations and, over time, effects on positive support become non-additional. However, combining the two interventions leads to a significant reduction in strong opposition to carbon taxation by over 20%. This effect persists for several months and is concentrated among Republicans and Independents. One potential mechanism for which we find evidence is that norm-based messaging causally reduces the perceived political bias of subsequent policy explanation. This is in line with the notion that, in polarized settings, factual information itself can become politicized.

[Working paper, 2026]

Abstract: Scalable behavioural interventions often struggle to engage the cognitive and psychological mechanisms that underlie durable changes in preferences and habits. This study provides a proof of concept for an underexplored intervention format: edutainment through video games. Partnering with a large video game company, we develop a game that embeds educational content on sustainable food consumption into an entertaining storyline. In a pre-registered field experiment (N = 4,034 UK adults), participants are randomly assigned to play either one of three treatment versions of the game or a control version without environmental content. Real-world food choice behaviour is measured through incentivised online supermarket tasks. Relative to the control group, treated participants select grocery baskets with 20% lower environmental impact immediately after gameplay, an effect that remains at 8–10% in a follow-up 2–3 weeks later. Behavioural change results from a combination of knowledge gains, short-term salience and preference change. Strikingly, effects were particularly persistent among subjects with low baseline sustainability. Further evidence suggests that the intervention was effective partly because it provided an enjoyable experience and affected a rich set of beliefs and attitudes, including personal norms, efficacy, and perceived social norms.

[short video presentation at AFE, 2020]

Abstract: Goal-setting is ubiquitous in the modern digitized world abundant with quantifiable information about individual behavior. We provide causal evidence on the effects of goal-setting and feedback from a field experiment in the context of everyday resource conservation in Singapore (N = 525 households). We randomly assign exogenous goals coupled with real-time feedback via smart meters and collect fine-grained behavioral measures over a duration of up to 6 months. Our main findings are as follows: (i) goal-setting substantially increases the conservation effect of feedback provision; (ii) the relationship between goal difficulty and effort appears to be non-monotonic but reverse U-shaped instead; (iii) all effects remain stable over the entire duration of the study; (iv) hazard rates of individual showers suggest that effort is particularly strong when a goal is in sight (bunching) but quickly dies off as soon as it becomes out of reach. These results are best explained by a fixed-penalty model instead of a loss-aversion-model with goals as reference points.

Abstract: High-stakes decisions and evaluations are often delegated to committees of experts. The success of information aggregation in a committee in turn depends on its institutional features and the incentives they generate. One important feature is whether opinions of individual members are made public or not. In this paper, we study the effect of a transparency reform in professional figure skating on performance evaluation by committee members. Prior to the reform, individual judges’ scores were only published anonymously, but scores were published openly from the 2016-17 season onwards. Using a difference-in-differences design, we find that, post-reform, the within-committee dispersion of (artistic) scores decreased, indicating a larger degree of conformity. This effect is stronger for high-profile competitions, which could be due to higher levels of anticipated public scrutiny. However, we find no reduction in nationalistic bias following the reform. Our empirical results are consistent with a beauty contest model in which transparency affects judge evaluations through increased conformity concerns.

[Published version (open access)]

Abstract: Researchers are increasingly examining policy officials’ perceptions of public opinion on climate change. However, limited research has examined the perceptions of individuals who participate in international-level environmental policy meetings. Here we show that 2024 United Nations Environment Assembly attendees (N = 191) underestimate global public willingness to contribute 1% of their personal income to climate action by nearly half on average (37% versus 69% in actuality). This finding suggests that those who are directly and indirectly involved in setting global environmental policies may have a stronger public mandate for ambitious climate action than they realize. We discuss the implications of this finding and highlight the need for further research on international policy actors’ perceptions of public opinion; the factors that shape these perceptions; and how these perceptions may influence policy outcomes.

[Published version] [Working paper, 2023]

Abstract: Growing political polarization is often attributed to “echo chambers” among like-minded individuals and a lack of social interactions among contrary-minded individuals. We provide quasi-experimental evidence on the effects of in-person conversations on individual-level polarization outcomes, studying a large-scale intervention in Germany that matched pairs of strangers for private face-to-face meetings to discuss divisive political issues. We find asymmetric effects: conversations with like-minded individuals caused political views to become more extreme (ideological polarization); by contrast, conversations with contrary-minded individuals did not lead to a convergence of political views, but significantly reduced negative beliefs and attitudes toward ideological out-group members (affective polarization), while also improving perceived social cohesion more generally. These effects of contrary-minded conversations seem to be driven mostly by positive experiences of interpersonal contact.

[Published version]

Abstract: Energy efficiency improvements can play an important role in reducing emissions from residential buildings, yet consumer decisions involving energy costs can be subject to bounded rationality due to, e.g., inattention and myopia. We present evidence that long-term, high-stakes decisions in the housing market are influenced by short-term contextual factors. Using data on housing transactions through a large online platform in Germany, we document that houses purchased following unusually cold weather tend to be more energy efficient, while the reverse is not true for unusually warm weather. This asymmetry suggests that the effect of temperature fluctuations on energy efficiency demand may be driven by salience of heating costs.

[Published version] [Working paper, 2021] [Data and code available upon request]

Abstract: Behavioral policy often aims at overcoming biases due to, e.g., imperfect information or inattention. When there are multiple sources of bias, interventions targeting different sources each may be complements: each intervention becomes more effective when combined with others. We test this in a field experiment on energy conservation in a resource-intensive everyday activity (showering). One intervention, shower energy reports, primarily improves knowledge about environmental impacts; another intervention, real-time feedback, primarily increases salience of resource use. While only the latter reduced energy consumption when implemented in isolation, combining both interventions boosted this conservation effect by over 50%, indicating a striking complementarity.

[Published version] [Working paper, 2021] [Public data]

Abstract: The COVID-19 pandemic induces a social dilemma: engaging in preventive health behaviors is costly for individuals but generates benefits that also accrue to society at large. The extent to which individuals internalize the social impact of their actions may depend on their prosociality, i.e., the willingness to behave in a way that mostly benefits other people. We conduct a nationally representative online survey in Germany (N = 5,843) to investigate the role of prosociality in reducing the spread of COVID-19 during the second coronavirus wave. At the individual level, higher prosociality is strongly positively related to compliance with public health behaviors such as mask wearing and social distancing. A one standard deviation (SD) increase in prosociality is associated with a 0.3 SD increase in compliance (p < 0.01). At the regional (NUTS-2) level, a one SD higher average prosociality is associated with an 11% lower weekly incidence rate (p < 0.01), and a 2%p lower weekly growth rate (p < 0.01) of COVID-19 cases, controlling for a host of demographic and socio-economic factors. This association is driven by higher compliance with public health behaviors in regions with higher prosociality. Our correlational results thus support the common notion that voluntary behavioral change plays a vital role in fighting the pandemic and, more generally, that social preferences may determine collective action outcomes of a society.

Abstract: Adoption of digital contact tracing (DCT) apps can provide critical relief for public health authorities in ring-fencing outbreaks of infectious diseases, especially when infection incidence is high. We conduct a large-scale randomized online experiment (N = 1,115,404) on social media to encourage adoption of the German DCT app during the COVID-19 pandemic. Our intervention provides locally-targeted feedback and regional comparisons on county-level incidence rates, in addition to the standard promotion video used by the German government. Providing the information increases view-rates and clickthrough rates of the ad by 30% compared to a regular promotion video for the app. Highlighting that one’s county is above the state average increases ad viewing and click-through rates by an additional 15%. Thes effects are largely driven by higher initial attention to the ad, i.e. the extensive margin. However, we observe an overall negative relationship between the effectiveness of the treatment and local incidence rates, indicating an adverse pattern of heterogeneity. We test the same interventions in separate study using a representative online survey (N = 6,060) and observe small but statistically significant treatment effects on favorability towards the contact tracing app.

Abstract: Many policymakers and environmental campaigners promote small pro-environmental actions in the hope that these changes will lead to larger behavioral changes. However, the empirical and theoretical literature on pro-environmental spillover effects yields mixed results. Yet, to evaluate the net benefits of a program, it is important to consider the side effects of an intervention. In a randomized controlled field trial with a fairly representative sample over 4 to 6 months with real-world data from 525 households (2,220 individuals), we analyze whether real-time feedback on water consumption in the shower induces spillover effects on other domestic water uses. Overall, our findings show no statistically significant reductions in water consumption beyond the directly targeted behavior. Moreover, we find suggestive evidence that the best intervention for a narrow outcome is not necessarily the most efficient one for overall pro-environmental behavior. Lastly, we find positive spillover effects on overall resource conservation for individuals with above-average water consumption in the shower during the baseline period.