Welcome! I am a Ph.D. candidate in economics at the University of Bonn.

In Fall 2023, I will be a Postdoctoral Scholar at the University of Chicago and Universidad del CEMA as part of the Joint Initiative for Latin American Experimental Economics. In Fall 2024, I will join the Erasmus School of Economics in Rotterdam as an tenure-track Assistant Professor of Finance.

My research fields are behavioral economics and household finance. In particular, I examine determinants and consequences of financial and moral decision-making using experiments, surveys, and linked survey-administrative data.

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Email: luca.henkel@uni-bonn.de
Twitter: @Henkel_Lu
Luca Henkel

Working Papers

Proud to Not Own Stocks: How Identity Shapes Financial Decisions | with Christian Zimpelmann

Current version: January 2023

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This paper introduces a key factor influencing households’ decision to invest in the stock market: how people view stockholders. Using survey data from the US and the Netherlands, we first document that the overwhelming majority of respondents view stockholders negatively - they are perceived as greedy, gambler-like, and selfish individuals. We then provide experimental evidence that such perceptions of identity-relevant characteristics causally influence decision-making: if people view stockholders more negatively, they are less likely to choose stock-related investments. Furthermore, by linking survey and administrative data, we show that negative perceptions strongly predict households’ stock market participation, more so than leading alternative determinants. Beyond investment decisions, perceptions predict individuals’ polarizing behavior towards stockholders, support for taxation and regulation of financial markets, and misreporting in surveys. Our findings provide a novel explanation for the puzzlingly low stock market participation rates around the world, new perspectives on the malleability of financial decision-making, and evidence for the importance of identity in economic decision-making.

Ends versus Means: Kantians, Utilitarians and Moral Decisions | with Roland Bénabou and Armin Falk

Current version: November 2022

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Choosing the morally right action can be based on the ends resulting from the decision - the Consequentialist view - or on the conformity of the means involved with some overarching notion of duty - the Deontological view. Using a series of experiments, we investigate the overall prevalence and the consistency of consequentialist and deontological decision-making, when these two moral principles come into conflict. Our design includes a real-stakes version of the classical trolley dilemma, four novel games that induce ends-versus-means tradeoffs, and a rule-following task. These main games are supplemented with six classical self-versus-others choice tasks, allowing us to relate consequential/deontological behavior to standard measures of prosociality. Across the six main games, we find a sizeable prevalence (20 to 40%) of non-consequentialist choices by subjects, but no evidence of stable individual preference types across situations. In particular, trolley behavior predicts no other ends-versus-means choices. Instead, which moral principle prevails appears to be highly context-dependent. In contrast, we find a substantial level of consistency across self-versus-other decisions, but individuals’ degree of prosociality is unrelated to how they choose in ends-versus-means tradeoffs that only affect others.

Experimental Evidence on the Relationship between Perceived Ambiguity and Likelihood Insensitivity

Current version: June 2022 | Games and Economic Behavior, Revise and Resubmit

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Observed individual behavior in the presence of ambiguity is characterized by insufficient responsiveness to changes in subjective likelihoods. Such likelihood insensitivity under ambiguity is integral to theoretical models and predictive of behavior in many important domains such as financial decision-making. However, there is little empirical evidence on its causes and determining factors. This paper investigates the role of beliefs in the form of ambiguity perception - the extent to which a decision-maker has difficulties assigning a single probability to each possible event - as a potential determinant. Using an experiment, I exogenously vary the degree of ambiguity while eliciting measures of likelihood insensitivity and ambiguity perception. The results provide strong support for an ambiguity perception based explanation of likelihood insensitivity. Not only are the two measures highly correlated on the individual level, but changes in ambiguity perception due to the exogenous variation also directly induce changes in likelihood insensitivity. My evidence thus substantiates the perception based interpretation of likelihood insensitivity brought forward by multiple prior models in contrast to preference based explanations of other commonly used models.

Eliciting Moral Preferences: Theory and Experiment | with Roland Bénabou, Armin Falk, and Jean Tirole

Current version: May 2022

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We study the extent to which a person’s moral preferences can be inferred from their choices, and how behaviors that appear deontologically motivated should be interpreted. Comparing direct elicitation (DE) and multiple-price list (MPL) mechanisms, we characterize how image motives inflate the extent of prosocial behavior. The resulting signalling bias is shown to depend on the interaction between elicitation method and visibility level: it is greater under DE for low reputation concerns, and greater under MPL for high ones. We test the model’s predictions in an experiment with life-saving donations and find the key crossing effect predicted by the theory.

Mapping motivational bias in recalling the SARS-CoV-2 pandemic | with Philipp Sprengholz, Robert Böhm, and Cornelia Betsch

Current version: May 2023

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How people recall the SARS-CoV2 pandemic is likely to prove crucial in future societal debates around pandemic preparedness and appropriate political action. Beyond simple forgetting, recall may be distorted by strong motivations and anchoring perceptions on the current situation. There is evidence of strong polarization in how vaccinated and unvaccinated people perceived the ongoing situation during the SARS-CoV2 pandemic. However, it remains unclear how these differences affect recall. Here we show based on three studies across 11 countries (total N = 10,242) that recall of perceived risk, trust in institutions and protective behaviours depend strongly on current evaluations. While both vaccinated and unvaccinated individuals were affected by this bias, people who identified strongly with their vaccination status—whether vaccinated or unvaccinated—tended to exhibit greater and opposite distortions of recall. As biased recall was not reduced by incentivizing accurate recall or by providing information about common recall errors, it seems that motivation and identity influence the direction in which evaluations of the past are distorted. Individual post-pandemic evaluations were found to be linked to future behavioural intent, including adherence to regulations during any future pandemics or punishing politicians and scientists. Taken together, these findings indicate that historical narratives about the COVID-19 pandemic are motivationally biased, sustain societal polarization between vaccinated and unvaccinated groups and are likely to hamper preparation for future pandemics. The fact that negative ex-post evaluations of the pandemic are accompanied by anti-system tendencies and a desire to punish suggests that any future measures must look beyond immediate public health implications to the longer-term consequences for societal cohesion and trust.


The Association Between Vaccination Status Identification and Societal Polarization | with Philipp Sprengholz, Lars Korn, Cornelia Betsch, and Robert Böhm

Nature Human Behaviour, 2023, 7(2): 231-239

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Public discord between those vaccinated and those unvaccinated for COVID-19 has intensified globally. Theories of intergroup relations propose that identifying with one’s social group plays a key role in the perceptions and behaviors that fuel intergroup conflict. We test whether identification with one’s vaccination status is associated with current societal polarization. The study draws on panel data from samples of vaccinated (n = 3,267) and unvaccinated (n = 2,038) respondents in Germany and Austria that were collected in December 2021, February, March, and July 2022. The findings confirm that vaccination status identification (VSI) explains substantial variance in a range of polarizing attitudes and behaviors. VSI was also related to higher psychological reactance toward mandatory vaccination policies among the unvaccinated. Higher levels of VSI reduced the gap between intended and actual counter-behaviors over time by the unvaccinated. VSI appears to be an important measure for predicting behavioral responses to vaccination policies.

Different Interventions for COVID-19 Primary and Booster Vaccination? Effects of Psychological Factors and Health Policies on Vaccine Uptake | with Philipp Sprengholz, Robert Böhm, and Cornelia Betsch

Medical Decision Making, 2023, 43(2): 239-251

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Background: Mitigation of the COVID-19 pandemic requires continued uptake of SARS-CoV-2 vaccines. To increase vaccination intention and uptake, key determinants of primary and booster vaccination need to be understood and potential effects of vaccination policies must be examined. Design: Using experimental data collected in Germany in February 2022 (n = 2,701), this study investigated (a) predictors of primary and booster vaccination, and (b) potential effects of policies combining vaccination mandates and monetary incentives. Results: Compared to unvaccinated participants, those with primary vaccination were less complacent, more often understood the collective protection afforded by vaccination, and less often endorsed conspiracy-based misinformation. Compared to participants with primary vaccination, boosted individuals were even less complacent, exhibited fewer conspiracy-based beliefs, perceived fewer constraints by prioritizing vaccination over other things, and more often favored compliance with official vaccination recommendations. Support for and reactance about vaccination mandates depended on vaccination status rather than policy characteristics, regardless of mandate type or incentives (up to 500 euro). While unvaccinated individuals rejected policy provisions and declined vaccination, boosted individuals indicated mid-level support for mandates and showed high vaccination intention. Among vaccinated individuals, higher incentives of up to 2,000 EUR had a considerable positive effect on the willingness to get boosted, especially in the absence of a mandate. Conclusions: While mandates may be needed to increase primary vaccination, our results indicate that financial incentives could be an alternative to promote booster uptake. However, combining both measures for the same target group seems inadvisable in most cases.

Payments and Freedoms: Effects of Monetary and Legal Incentives on COVID-19 Vaccination Intentions in Germany | with Philipp Sprengholz and Cornelia Betsch

PLOS ONE, 2022, 17(5): 1-11

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Monetary and legal incentives have been proposed to promote COVID-19 vaccination uptake. To evaluate the suitability of incentives, an experiment with German participants examined the effects of payments (varied within subjects: 0 to 10,000 EUR) and freedoms (varied between subjects: vaccination leading vs. not leading to the same benefits as a negative test result) on the vaccination intentions of previously unvaccinated individuals (n = 782). While no effect could be found for freedoms, the share of participants willing to be vaccinated increased with the payment amount. However, a significant change required large rewards of 3,250 EUR or more. While monetary incentives could increase vaccination uptake by a few percentage points, the high costs of implementation challenge the efficiency of the measure and call for alternatives. As experimental data suggest that considering vaccination as safe, necessary, and prosocial increases an individual’s likelihood of wanting to get vaccinated without payment, educational campaigns should emphasize these features when promoting vaccination against COVID-19.


2022 Behavioral Economics (Undergraduate) | University of Bonn
2021–22 Research Module in Management and Applied Microeconomics (Graduate) | University of Bonn
2020–21 Seminar on Scientific Work Methods (Undergraduate) | University of Bonn