Publications

"Extreme justifications fuel polarization"

Christiane Buschinger, Markuy Eyting, Florian Hett & Judd Kessler

How does polarization --- as measured by mistreatment of political rivals --- spread? In an online experiment, participants choose between splitting financial resources equally or discriminating against a member of the opposing political party. We vary the information subjects receive about others’ choices and justifications for discrimination. Exposure to extreme justifications for discrimination increases discrimination --- particularly in a polarized environment, when many others are already discriminating --- and it leads participants to adopt more extreme justifications themselves. Our findings suggest a self-reinforcing dynamic that may fuel polarization: Exposure to extreme statements increases polarization and the prevalence of extreme reasoning.

Economic Journal, conditionally accepted.

"The detrimental effect of group size on institution formation"

Julian Detemple & Michael Kosfeld

A solution for the provision of public goods is the formation of institutions that change the rules of the game, e.g., through sanctions or enforced cooperation commitments. While prior laboratory experiments document a positive effect of the opportunity to form such institutions on cooperation in small groups, groups in the field are typically much larger. We test the causal effect of group size on institution formation and show that institutions almost never form successfully as group size increases from four to just eight or twelve individuals. Prior results on the formation of institutions, such as those of Kosfeld et al. (2009), thus do not generalize to larger groups. Our findings document that individuals are less willing to be bound by the rules of the institution, while willing individuals struggle to reach a unanimous decision as group size increases.

Journal of Economic Behavior & Organization, 240 (2025), 107298.
https://doi.org/10.1016/j.jebo.2025.107298

"The effect of shingles vaccination at different stages of the dementia disease course"

Min Xie, Markus Eyting, Christian Bommer, Haroon Ahmed & Pascal Geldsetzer

Using natural experiments, we have previously reported that live-attenuated herpes zoster (HZ) vaccination appears to have prevented or delayed dementia diagnoses in both Wales and Australia. Here, we find that HZ vaccination also reduces mild cognitive impairment diagnoses and, among patients living with dementia, deaths due to dementia. Exploratory analyses suggest that the effects are not driven by a specific dementia type. Our approach takes advantage of the fact that individuals who had their eightieth birthday just after the start date of the HZ vaccination program in Wales were eligible for the vaccine for 1 year, whereas those who had their eightieth birthday just before were ineligible and remained ineligible for life. The key strength of our natural experiments is that these comparison groups should be similar in all characteristics except for a minute difference in age. Our findings suggest that live-attenuated HZ vaccination prevents or delays mild cognitive impairment and dementia and slows the disease course among those already living with dementia.

Cell, 188 (2025), 7049-7064.
https://doi.org/10.1016/j.cell.2025.11.007

"A natural experiment on the effect of herpes zoster vaccination on dementia"

Markus Eyting, Min Xie, Felix Michalik, Simon Heß, Seunghun Chung & Pascal Geldsetzer

Neurotropic herpesviruses may be implicated in the development of dementia. Moreover, vaccines may have important off-target immunological effects. Here we aim to determine the effect of live-attenuated herpes zoster vaccination on the occurrence of dementia diagnoses. To provide causal as opposed to correlational evidence, we take advantage of the fact that, in Wales, eligibility for the zoster vaccine was determined on the basis of an individual’s exact date of birth. Those born before 2 September 1933 were ineligible and remained ineligible for life, whereas those born on or after 2 September 1933 were eligible for at least 1 year to receive the vaccine. Using large-scale electronic health record data, we first show that the percentage of adults who received the vaccine increased from 0.01% among patients who were merely 1 week too old to be eligible, to 47.2% among those who were just 1 week younger. Apart from this large difference in the probability of ever receiving the zoster vaccine, individuals born just 1 week before 2 September 1933 are unlikely to differ systematically from those born 1 week later. Using these comparison groups in a regression discontinuity design, we show that receiving the zoster vaccine reduced the probability of a new dementia diagnosis over a follow-up period of 7 years by 3.5 percentage points (95% confidence interval (CI) = 0.6–7.1, P = 0.019), corresponding to a 20.0% (95% CI = 6.5–33.4) relative reduction. This protective effect was stronger among women than men. We successfully confirm our findings in a different population (England and Wales’s combined population), with a different type of data (death certificates) and using an outcome (deaths with dementia as primary cause) that is closely related to dementia, but less reliant on a timely diagnosis of dementia by the healthcare system. Through the use of a unique natural experiment, this study provides evidence of a dementia-preventing or dementia-delaying effect from zoster vaccination that is less vulnerable to confounding and bias than the existing associational evidence.

Nature, 641 (2025), 438-446.
https://doi.org/10.1038/s41586-025-08800-x

Claudia Landwehr, Christopher Ojeda & Paul Weingärtner

Depressive symptoms in citizens are a strong predictor of political non-participation and have considerable negative effects on motivation and political interest. Apparently, the way in which depressed citizens relate to democratic institutions significantly differs from that of other citizens. In this letter, we therefore explore the relationship between depressive symptoms and the assessment of democracy. We test whether depressive symptoms, and the negativity bias they engender, lead to more negative evaluations of democratic institutions, practices and performance. Drawing on data from the European Social Survey, we find depression has negative effects on the assessment of democracy across countries and evaluative dimensions, and that on average, people with depressive symptoms have more negative views about democracy in their own country. An analysis of longitudinal data from Germany provides further evidence by demonstrating that intrapersonal changes in depression over time lead to changes in democratic evaluations.

Electoral Studies, 95 (2025), 102928.
https://doi.org/10.1016/j.electstud.2025.102928

"Domestic financial conditions and MNCs’ global competitiveness: evidence from the Swiss franc shock"

Christian Eufinger, Andrej Gill & Florian Hett

Our study examines the influence of the local financial conditions in a multinational corporation’s (MNC) home country on its global strategy and market position. Establishing a headquarters in a country grants legitimacy with local stakeholders, which enhances firms’ access to local capital markets. Consequently, MNCs headquartered in a country with favorable financial conditions might gain an advantage over MNCs based in countries with a less advantageous financial environment. To analyze this hypothesis, we utilize local projections and a major policy shift by the Swiss National Bank in January 2015, which involved an exchange rate shock and a substantial interest rate cut to −0.75%. Our analysis shows that Swiss-based MNCs, benefiting from lower domestic interest rates, significantly outperformed their EU-based rivals in terms of investment rates (8.4–9.7% points higher) and employment growth (6.7–9.8% points higher). Moreover, we show that this stimulating effect helped to offset the adverse consequences of the simultaneous appreciation of the domestic currency for Swiss-based MNCs in sectors more reliant on exports. Our results highlight the critical role of local financial conditions and, more broadly, local macroeconomic factors in shaping MNCs’ global strategies and competitive standing.

Journal of International Business Studies, 55(8) (2024), 1057-1068.
https://doi.org/10.1057/s41267-024-00703-9

"Belief Elicitation with Multiple Point Predictions"

Eyting, Markus and Patrick Schmidt

We propose a simple, incentive compatible procedure based on binarized linear scoring rules to elicit beliefs about real-valued outcomes - multiple point predictions. Simultaneously eliciting multiple point predictions with linear incentives reveals the subjective probability distribution without pre-defined intervals or probabilistic statements. We show that the approach is theoretically as robust as existing methods, while adapting flexibly to different beliefs. In a laboratory experiment, we compare our procedure to the standard approach of eliciting discrete probabilities on pre-defined intervals. We find that elicitation with multiple point predictions is faster, perceived as less difficult and more consistent with a subsequent decision. We further find that multiple point predictions are more accurate if beliefs vary between participants. Finally, we provide experimental evidence that pre-defined intervals anchor reports.

European Economic Review, 135 (2021), 103700.
https://doi.org/10.1016/j.euroecorev.2021.103700

"The Structure and Behavioral Effects of Revealed Social Identity Preferences"

Hett, Florian, Markus Kröll, and Mario Mechtel

A large body of evidence shows that social identity affects behaviour. However, our understanding of the substantial variation of these behavioural effects is still limited. We use a novel laboratory experiment to measure differences in preferences for social identities as a potential source of behavioural heterogeneity. Facing a trade-off between monetary payments and belonging to different groups, individuals are willing to forego significant earnings to avoid belonging to certain groups. We then show that individual differences in these foregone earnings correspond to the differences in discriminatory behaviour towards these groups. Our results illustrate the importance of considering individual heterogeneity to fully understand the behavioural effects of social identity.

Economic Journal, 130(632) (2020), 2569-2595.
https://doi.org/10.1093/ej/ueaa055

"Do Children Cooperate Conditionally? Adapting the Strategy Method for First-Graders"

Hermes, Henning, Florian Hett, Mario Mechtel, Felix Schmidt, Daniel Schunk, and Valentin Wagner

We develop a public goods game (PGG) to measure cooperation and conditional cooperation in young children. Our design addresses several obstacles in adapting simultaneous and sequential PGGs to children who are not yet able to read or write, do not possess advanced abilities to calculate payoffs, and only have a very limited attention span at their disposal. It features the combination of haptic offline explanation, fully standardized audiovisual instructions, computerized choices based on touch-screens, and a suitable incentive scheme. Applying our experimental protocol to a sample of German first-graders, we find that already 6-year-olds cooperate conditionally and that the relative frequency of different cooperation types matches the findings for adult subjects. We also find that neither survey items from teachers nor from parents predict unconditional or conditional cooperation behavior; this underlines the value of incentivized experimental protocols for measuring cooperation in children.

Journal of Economic Behavior & Organization, 179 (2020), 638-652.
https://doi.org/10.1016/j.jebo.2018.12.032

"Bank Rescues and Bailout Expectations: The Erosion of Market Discipline During the Financial Crisis"

Hett, Florian and Alexander Schmidt

We design a novel test for changes in market discipline based on the relation between firm-specific risk, credit spreads, and equity returns. We use our method to analyze the evolution of bailout expectations during the recent financial crisis. We find that bailout expectations peaked in reaction to government interventions following the failure of Lehman Brothers, and returned to pre-crisis levels following the initiation of the Dodd-Frank Act. We do not find such changes in market discipline for non-financial firms. Finally, market discipline is weaker for government-sponsored enterprises (GSEs) and systemically important banks (SIBs) than for investment banks.

Journal of Financial Economics, 126 (2017), 635-651.
https://doi.org/10.1016/j.jfineco.2017.10.003

Winner of the Sturm & Drang Prize for the best publication by a young researcher of the Faculty of Economics and Business Administration

"Social Identity and Social Free Riding"

Bernard, Mark, Florian Hett, and Mario Mechtel

We model individual identification choice as a strategic group formation problem. When choosing a social group to identify with, individuals appreciate high social status and a group stereotype to which they have a small social distance. A group's social status and stereotype are shaped by the (exogenous) individual attributes of its members and hence endogenous to individuals' choices. Unless disutility from social distance is strong enough, this creates a strategic tension as individuals with attributes that contribute little to group status would like to join high-status groups, thereby diluting the latters' status and changing stereotypes. Such social free-riding motivates the use of soft exclusion technologies in high-status groups, which provides a unifying rationale for phenomena such as hazing rituals, charitable activities or status symbols that is not taste-based or follows a standard signaling mechanism.

European Economic Review, 90 (2016), 4-17 (lead article).
http://dx.doi.org/10.1016/j.euroecorev.2016.01.001

"Can monetary incentives increase organ donations?"

Eyting, Markus, Arne Hosemann, and Magnus Johannesson

We test in an experiment if a monetary incentive or a charity incentive can motivate people to fill in the German organ donor card and thereby increase the number of organ donors. We find that a monetary incentive significantly increases the number of organ donors whereas the charity incentive does not.

Economics Letters, 142 (2016) 56–58
https://doi.org/10.1016/j.econlet.2016.03.005

"How Individual Characteristics Shape the Structure of Social Networks"

Girard, Yann, Florian Hett, and Daniel Schunk

We study how students’ social networks emerge by documenting systematic patterns in the process of friendship formation of incoming students; these students all start out in a new environment and thus jointly create a new social network. As a specific novelty, we consider cooperativeness, time and risk preferences – elicited experimentally – together with factors like socioeconomic and personality characteristics. We find a number of robust predictors of link formation and of the position within the social network (local and global network centrality). In particular, cooperativeness has a complex association with link formation. We also find evidence for homophily along several dimensions. Finally, our results show that despite these systematic patterns, social network structures can be exogenously manipulated, as we find that random assignments of students to groups on the first two days of university impacts the students’ friendship formation process.

Journal of Economic Behavior & Organization, 115 (2015), 197-216.
http://dx.doi.org/10.1016/j.jebo.2014.12.005