Selected Publications

Frequently, scholars and decision-makers criticize behavioral public policies for infringing on behavioral autonomy. This paper provides evidence from an online framed field experiment, in which participants encountered a recommendation, a default value, or a mandatory minimum contribution accompanied by varying information on the regulator, before contributing to climate protection and answering an autonomy-related questionnaire. Our findings show that decision-makers perceive defaults as more freedom threatening but not more annoying than recommendations. They perceive mandatory minimum contributions as more threatening to freedom and annoying than defaults. Intrinsic motivation moderates these differences. Framing the regulator as an expert reduces perceived threat to freedom and felt anger, while political source framing has no effect. We also provide suggestive, exploratory, correlational evidence on potential reasons that defaults reduce contributions more than other interventions for highly motivated people. A mediated moderation analysis shows that this is partly because subjects rate the default as more threatening and because this makes them angry. However, the latter finding has important caveats and demands for future research. Findings improve our understanding of how the effectiveness of behavioral interventions depends on decision-makers’ perceptions and how this can be leveraged by policymakers.
In SSRN, 2019

Policymakers discuss nudges as instruments to foster individual public good contributions. Contrary to the original aim of nudges, which is to improve decision outcomes for the individual, pro-social nudges aim to improve the social outcomes of individual behavior. This can potentially result in personal costs. Because the question of responsibility to contribute to public goods on an individual level is a tricky one, it is important to investigate whether vulnerable people are more susceptible to the influence of this type of nudges. We report evidence from a laboratory public goods experiment testing whether the effects of pro-individual, resp. pro-social defaults on behavior vary based on cognitive resource availability. Findings based on 476 independent observations do not show an interaction effect. Our findings inform public policy-making by shedding light on heterogeneous impacts of behavioral policies imposing individual costs to foster social benefits. This is important for the discussion on who should contribute to public good provision and how nudges may affect this. Thus, findings add to the debate on the ethics of nudges, as well as to the scientific understanding of the various nuances of libertarian paternalistic policies.
In SSRN, 2019

This paper investigates differences between a default, a recommendation, and a mandatory minimum contribution on private provision of a large scale public good (climate protection). Information on the regulator (neutral experimenter, expert or politician), its interaction with the intervention type, as well as with pre-intervention intrinsic motivation on voluntary contributions is analyzed. Data are from an online framed field experiment with a sample representative of the German internet using population. Main insights are: neither a recommendation nor a default close to the pre-intervention average change contributions; identifying the regulator reduces contributions when accompanying the recommendation, but not the default; contributions above the pre-intervention average are reduced by the default but increased by the mandatory minimum relative to the control; only the default negatively interacts with high intrinsic motivation; and regulator attributes neither interact with intrinsic motivation, nor with the type of intervention. The study contributes to the discussion of nudges as public policy instruments by comparing them to alternative interventions, i.e. pointing at or pushing contributions, and by shedding light on making the source of the intervention transparent.
In SSRN, 2018

Nudges receive growing attention as an effective concept to alter people’s decisions without significantly changing economic incentives or limiting options. However, being often very subtle and covert, nudges are also criticized as unethical. By not being transparent about the intention to influence individual choice they might be perceived as limiting freedom of autonomous actions and decisions. So far, empirical research on this issue is scarce. In this study, we investigate whether nudges can be made transparent without limiting their effectiveness. For this purpose we conduct a laboratory experiment where we nudge contributions to carbon emission reduction by introducing a default value. We test how different types of transparency (i.e. knowledge of the potential influence of the default, its purpose, or both) influence the effect of the default. Our findings demonstrate that the default increases contributions, and information on the potential influence, its purpose, or both combined do not significantly influence the default effect. Furthermore, we do not find evidence that psychological reactance interacts with the influence of transparency. Findings support the policy-relevant claim that nudges (in the form of defaults) can be transparent and yet effective.
Journal of Economic Psychology, 2018

Labeling news as fake is a recent phenomenon occurring predominantly online, and increasingly in political online environments. This paper investigates the influence of expressed doubt in media independence on trust in news reports on climate change, and on trust in more scientific sources. Evidence from a laboratory experiment does not suggest that reading a media-critic statement affects perceived trust in the media-, or the scientific source reporting on climate change. Bayesian analyses provide a practical interpretation of the null findings, and further analyses show that the statement decreases trust in the scientific source when subjects read the media article first. Findings add to the emerging literature on fake news, echo chambers and filter bubbles, suggesting that labeling stories or outlets as fake news may not affect public opinions. Further research is needed to substantiate this conclusion.
In SSRN, 2018


Climate Debate

In this project I use text-mining procedures to understand how we discuss climate change online. I quantitatively analyse online articles on climate change, both from skeptical and affirmative standpoints.

Effects of scarcity on pro-social nudges

This project aims at mapping the potential interactions between various forms of scarcity on the performance of pro-social/ green nudges. Specifically, we use laboratory and field experiments to test whether economic, cognitive, and social scarcity change decision-makers proneness to nudges that aim to reduce negative externalities.

Green Nudging

This project evaluates the relative performance of nudges and conventional instruments to foster pro-environmental behavior.

Transparent Nudges

This project evaluates the impact of transparency on nudge-performance.

Climate Change Skepticism

This project investigates causes underlying public skepticism towards the occurence of man-made climate change, as well as differences and similarities between arguments underlying both positions.

Recent Posts

More Posts

A discounting app


Science is there to answer questions, and it is a powerful tool at that. In this post I outline how I approach the task of coming up with research questions, how to answer them and how to create a publishable manuscript describing this procedure. It is very idiosyncratic, but I hope that it might be useful for some readers, especially students.


For one of my projects I needed to download text from multiple websites. I did this with rvest and dplyr. While this can be relatively easy if the sources come from the same websites, it can be pretty tedious when the website hosts are various. The reason is how the content is kept in the HTML of the website. Assume that you want to extract the title, author information, publish date, and of course the main article text. You can access that information via CSS or XPath. The following text will walk you through an example and provide the relevant code.



Behavioral Environmental Economics and Policy

University of Hamburg, Fall 2019/ 2020

Aktuelle Probleme der Umweltökonomik

University of Hamburg, Summer 2019, Fall 20192020

The Economics of Climate Change

University of Hamburg, Summer 2019

Verhaltensökonomik für die Umwelt

University of Hamburg, Fall 2018/ 2019


CorrelAid e.V.

We are a network of young data analysts that wants to change the world with a more inclusive, integrated and innovative approach to data analysis. CorrelAid builds on three pillars: We take a pioneer role in analytics consulting for Non-Profit-Organisations. We connect young, driven data scientists and offer them the possability to apply and develop their skills on real-world problems. Last but not least, we start a dialogue on the potential of data and analytics for the civic society.

Seehilfe e.V.

Projekt Seehilfe e.V. aims on a long-term basis to strengthen integrative and educational structures for refugees arriving in Europe by providing workshops and general recreational offerings, as well as administrational and bureaucratic support, especially in Sicily.


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