About me

I am currently a research fellow at the Federal Institute for Population Research (BiB) and a postdoctoral fellow at the Mannheim Centre for European Social Research (MZES). My current research focuses on intergroup relations, migration, discrimination and cooperative behavior in modern societies. Other research projects examine the preceptions and consequencs of physical attractiveness. My research draws on a range of experimental and quasi-experimental methods, including original lab-in-the-field, survey and field experiments.

Recently, I have also been an Interim Professor (“Vertretungsprofessur”) of Quantitative Methods and Economic Sociology at the Johannes Gutenberg University, Mainz (2023-2024). Prior to joining the MZES, I held a postdoctoral position at the Carlo F. Dondena Centre for Research on Social Dynamics and Public Policy at Bocconi University in Milan, Italy. I hold a Ph.D. in Social and Political Sciences from the European University Institute in Florence, Italy.

I am an elected member of “Die Junge Akademie,” a joint project of the Berlin-Brandenburg Academy of Sciences and Humanities and the German National Academy of Sciences Leopoldina from 2021-2026. Together with my colleagues, we have recently published a guideline and practical advice for effective science communication (in German).

Together with Prof. Reinhard Schunck (University of Wuppertal), I am the PI of the research project “Pretty Integrated? Perceptions of immigrants’ physical attractiveness and consequences for integration outcomes” financed by the German Research Foundation (DFG) (2021-2025). In September 2024, I was honored to receive the Best Reviewer Award from the European Sociological Review.

Interests

  • intergroup relations
  • migration
  • discrimination
  • trust and cooperation
  • poverty and inequality

Education

  • Postdoctoral researcher at the Carlo F. Dondena Centre for Research on Social Dynamics and Public Policy, 2018

    Bocconi University in Milan, Italy

  • Ph.D. in Social and Political Sciences, 2016

    European University Institute in Florence, Italy

Research In Progress

The effects of Muslim immigration and demographic change on group boundaries in Germany

Gereke, Helbling, Kommol, Ünal, Szafran, Visser-Koomson Oct 2023
Increasing ethnic and religious diversity in many Western societies has sparked research on the consequences of this demographic change on intergroup relations. The impact of Muslim immigration in Europe has become a particularly salient topic in the political debate. Yet, it is unclear how prospective immigrant population growth and the numeric increase of Muslims impact group boundaries. We use a survey experiment to examine the effects of demographic shifts on how the majority draws group boundaries in Germany. The results show that information about a growing share of immigrants or Muslims increases perceptions of threat, leading Germans to classify ambiguous German / Middle Eastern and North African (MENA) as more likely to have a migration background. Further, such information increases negative feelings towards individuals with unambiguous MENA physical appearance. These findings contribute to a growing literature on demographic change and how group boundaries are drawn in diverse European societies.

Religion, Religiosity and Perceived Trustworthiness: Experimental Evidence from a Vignette Study in Germany

Gereke, Hellyer, Fadavi, Zhang Oct 2023
Muslim immigrants in European societies are commonly perceived to be more religious than their Christian counterparts. Moreover, since traditional religious beliefs and practices often run counter to modern, liberal values, Muslims’ religiosity is argued to contribute to an additional burden of prejudice directed at religious (but not secular) Muslims. At the same time, could Muslims’ religiosity paradoxically increase their perceived trustworthiness? Building on evidence from recent research suggesting that religiosity functions as a costly signal of benevolent intentions, we test the hypothesis that religious Muslims are more trusted than their secular counterparts. We present evidence from a survey experiment embedded within the German Internet Panel, a random offline recruited probability sample of the general population in Germany aged 16-75, in which respondents are presented with a hypothetical lost wallet scenario. Our design varies both the religious heritage (Muslim vs. Christian) and religiosity (highly religious vs. secular vs. atheist) of the wallet’s finder and measure beliefs about the likelihood that the wallet will be returned.

Publications

Baldassarri, Delia, Gereke, Johanna, and Schaub, Max (2024) Prosociality Beyond In-Group Boundaries: A Lab-in-the-Field Experiment on Selection and Intergroup Interactions in a Multiethnic European Metropolis

Sociological Science 11: 815-853. Sep 2024
How does prosocial behavior extend beyond in-group boundaries in multiethnic societies? The differentiation of Western societies presents an opportunity to understand the tension between societal pressures that push people outside the comfort zones of their familiar networks to constructively interact with unknown diverse others and the tendency toward homophily and in-group favoritism. We introduce a three-step model of out-group exposure that includes macrostructural conditions for intergroup encounters and microlevel dynamics of intergroup selection and interaction. Using lab-in-the-field experiments with a large representative sample of Italian natives and immigrants from the multiethnic city of Milan, we find that, when pushed to interact with non-coethnics, Italians generally treat them similarly to how they treat coethnics and value signs of social and market integration. However, when given the opportunity to select their interaction partners, Italians favor coethnics over immigrants. Taken together, these results help reconcile classical findings concerning the positive effects of intergroup contact with evidence documenting the persistence of out-group discrimination in selection processes.

Hellyer, Joshua, and Gereke, Johanna (2024) The shadow of fear: hate crime victimization and stress after Charlottesville

Frontiers in psychology, 15: 1384470 Jun 2024
Recent years have witnessed an increase in highly publicized attacks against members of minority groups. To date, scholarship has primarily focused on the tendency for such trigger events to generate violent aftershocks. However, we hypothesize that trigger events create a climate of fear that may also significantly impact minorities’ mental health and well-being. To test our conjuncture, we draw upon both national survey data as well as federal hate crime data in combination with a natural experiment involving the Unite the Right rally and vehicle attack in Charlottesville, Virginia. We first show that there was an increase in anti-Black hate crimes in the two weeks following Charlottesville. We also link the Charlottesville attack to an increase in stress about personal hate crime victimization among African-Americans. Interestingly, these results are confined to African-Americans, suggesting that both violent aftershocks and the general climate of fear may be racially bounded.

Kretschmer, David, Gereke, Johanna, Winter, Fabian and Zhang, Nan (2023) No differential effects of classroom ethnic composition on native and immigrant friendship segregation: Comment on Smith et al., 2016

American Journal of Sociology, Volume 129 Number 2 (September 2023): 570-585 Nov 2023
What is the relationship between classroom ethnic composition and patterns of ethnic friendship segregation amongst native and immigrant adolescents? In a 2016 AJS article, Smith et al. analyzed data on adolescents’ friendship networks from four European countries and found differential effects of classroom composition on natives’ and immigrants’ friendship choices. In this comment, we identify estimation problems in a large number of classroom networks included in Smith et al.’s original study. We demonstrate that immigrant homophily cannot be meaningfully estimated in many networks containing insufficient numbers of immigrant students from the same ethnic group. After accounting for these estimation problems at the network level, our re-analyis provides little evidence that classroom composition has differential effects for native and immigrant homophily.

Hellyer, Joshua, Hellriegel, Emily, Gereke, Johanna and Schunck, Reinhard (2023) Pretty unequal? Immigrant-native differences in returns to physical attractiveness in Germany

Journal of Economic Behavior & Organization, 2023:215, pp.107-119 Sep 2023
How do the economic returns to physical attractiveness vary between immigrants and natives? Despite a growing literature on the beauty premium, previous scholarship has not examined whether the size of this premium might vary according to immigrant status, an important axis of social stratification in European societies. We study this question in the German labor market using longitudinal data from a large, randomly drawn nationwide sample that includes interviewer ratings of respondents’ physical attractiveness. Results from a multiverse analysis provide strong evidence of a beauty premium for native German men and women. However, we find mixed results for ethnic minority groups. These results highlight how perceived physical attractiveness is linked to labor market stratification.

Gereke, Johanna and Ruedin, Didier (2023) Trusting and Reciprocating Trust of Citizens versus Non-Citizens: Experimental Evidence from the U.S., South Africa and Switzerland

Socius: sociological Research for a Dynamic World Aug 2023
We examine how trust and trustworthiness varies with the citizenship status of the alter in three democratic countries with varying sharres of immigrants and levels of economic development: the United States, South Africa, and Switzerland. Trust games were implemented in representative surveys. While we find significant differences in overall levels of trust and trustworthiness across countries, we do not find any significant differences in the degree to which participants trusted or reciprocated trust of interaction partners with the same vs. foreign citizenship status in any of the three countries. Our results suggest that citizenship status is not a salient identity marker to shape trust or trustworthiness in these types of interpersonal interactions.

Auer, D., Gereke,J and Schaub M (2023) Spiritual practices predict migration behavior

Scientific reports Aug 2023
Each year, several thousand migrants from Sub-Saharan Africa die attempting to reach Europe’s southern shores. Social scientists and policymakers have been puzzling over the question why so many people are prepared to take this extremely high risk of dying. Drawing on panel data from over 10,000 individuals in The Gambia, one of the countries with the highest emigration rates in the world, we show that cultural beliefs in terms of spiritual practices are strongly associated with a decreased perception of one’s own risk of dying on the migration journey. We find that consulting a healer for spiritual protection predicts migration plans and actual migration behavior.

Gereke, Johanna, et al.Demographic Change and Group Boundaries in Germany: The Effect of Projected Demographic Decline on Perceptions of Who Has a Migration Background

Sociological Science 9, 206-220 May 2022
In many Western societies, the current “native” majority will become a numerical minority sometime within the next century. How does prospective demographic change affect existing group boundaries? An influential recent article by Abascal (2020) showed that white Americans under demographic threat reacted with boundary contraction—that is, they were less likely to classify ambiguously white people as “white.” The present study examines the generalizability of these findings beyond the American context. Specifically, we test whether informing Germans about the projected decline of the “native” population without migration background affects the classification of phenotypically ambiguous individuals. Our results show that information about demographic change neither affects the definition of group boundaries nor generates negative feelings toward minority outgroups. These findings point to the relevance of contextual differences in shaping the conditions under which demographic change triggers group threat and boundary shifts..

N. Zhang, J. Gereke, D. Baldassarri (2022) Everyday Discrimination in Public Spaces: A Field Experiment in the Milan Metro

European Sociological Review, 38.5: 679-693 Feb 2022
A large scholarship documents discrimination against immigrants and ethnic minorities in institutional settings such as labour and housing markets in Europe. We know less, however, about discrimination in informal and unstructured everyday encounters. To address this gap, we report results from a large-scale field experiment examining the physical avoidance of immigrants as an unobtrusive yet important measure of everyday discrimination in a multiethnic European metropolis. In addition to varying confederates’ migration background and race, we also vary signals of status (business versus casual attire) in order to shed light on the mechanisms underlying discriminatory patterns. We find that natives are averse to contact with Nigerian confederates, but do not discriminate against Chinese confederates. Furthermore, manipulating confederates’ attire has little effect on natives’ behaviour. Overall, our results highlight the everyday burdens borne particularly by individuals of African descent in commonplace, ‘street-level’ encounters.

J. Gereke, M. Schaub, D. Baldassarri (2022). Immigration, integration and cooperation: experimental evidence from a public goods game in Italy

Journal of Ethnic and Migration Studies, 48(15), 3761-3788 Jul 2021
Immigration has rapidly changed the demographic profile of most Western European societies, increasing their ethnic diversity. Some cross-disciplinary literature comparing homogeneous and diverse communities provides observational evidence of a link between high levels of ethnoracial diversity and lower levels of public goods provision. While these results are often interpreted as driven by context/interaction effects, whereby individuals lower their cooperativeness in response to the presence of non-coethnics, they could also be explained by composition effects – immigrants having different baseline levels of cooperativeness, and thereby lowering average cooperation rates. To disentangle these effects, we conducted a lab-in-the-field experiment with a sample of Italians and immigrants from Morocco and the Philippines residing in Milan. In our public goods experiment, participants were randomly assigned to either homogeneous or ethnically mixed groups. We find that Italians behave similarly in both homogeneous and heterogeneous groups, thus contradicting arguments about the negative effects of diversity on the native population, while there are both compositional and interactional effects when considering the behaviour of Moroccan and Filipino immigrants, respectively. Moreover, differences largely disappear when we consider only the behaviour of more socio-economically integrated immigrants, highlighting the need for a more processual understanding of cooperation in multiethnic communities.

M. Schaub, J. Gereke, D. Baldassarri (2021). Strangers in Hostile Lands: Exposure to Refugees and Right-wing Support

Comparative Political Studies, 54(3-4), 686-717 Sep 2020
Does local exposure to refugees affect right-wing support and anti-immigrant sentiments? This paper studies the allocation of refugees to the rural hinterlands of Eastern Germany during the refugee crisis of 2015. Similar to non-urban regions elsewhere, the area has seen a major shift towards the political right, despite minimal previous exposure to foreigners. We draw on electoral records and original data collected among 1,320 German citizens from 236 municipalities, half of which received refugees. Two conditions allow for causal identification: a policy allocating refugees following strict administrative rules, and a matching procedure rendering treated and control municipalities statistically indistinguishable. Our survey and behavioral measures confirm the presence of widespread anti-immigrant sentiments, but these are entirely unaffected by the presence of refugees in respondents’ hometowns. If anything, local exposure to refugees served as a ‘reality check’, pulling both right- and left-leaning individuals more towards the center.

J. Gereke, M. Schaub, D. Baldassarri. Gendered discrimination against immigrants: experimental evidence

Frontiers in Sociology, 5, 59. Sep 2020
Recent migration from Muslim-majority countries has sparked discussions across Europe about the supposed threat posed by new immigrants. Young men make up the largest share of newly arrived immigrants and this demographic is often perceived to be particularly threatening. In this article, we compare pro-sociality and trust towards immigrants from Muslim-majority countries, focusing on gender differences in treatment. We study these questions using behavioral games that measure strategic (trusting) and non-strategic (pro-social) behavior. Our data comes from measures embedded in a large survey of residents of Germany’s eastern regions, where anti-immigrant sentiments are high. We find that Germans are similarly pro-social toward immigrant men and women in non-strategic situations, but are significantly less likely to trust immigrant men (but not women) in strategic encounters. These findings provide evidence that immigrants’ gender can be an important factor conditioning the behavior of the majority population, but also caution that (gendered) ethnic discrimination may be situationally dependent. Future research should further examine the exact mechanisms underlying this variation in discriminatory behavior.

Gereke, J., & Gërxhani, K. Experimental Economics and Experimental Sociology

Oxford research encyclopedia: economics and finance. Nov 2019
Experimental economics has moved beyond the traditional focus on market mechanisms and the “invisible hand” by applying sociological and socio-psychological knowledge in the study of rationality, markets, and efficiency. This knowledge includes social preferences, social norms, and cross-cultural variation in motivations. In turn, the renewed in­ terest in causation, social mechanisms, and middle-range theories in sociology has led to a renaissance of research employing experimental methods. This includes laboratory experiments but also a wide range of field experiments with diverse samples and settings. By focusing on a set of research topics that have proven to be of substantive interest to both disciplines—cooperation in social dilemmas, trust and trustworthiness, and social norms—this article highlights innovative interdisciplinary research that connects experimental economics with experimental sociology. Experimental economics and experimental sociology can still learn much from each other, providing economists and sociologists with an opportunity to collaborate and advance knowledge on a range of underexplored topics of interest to both disciplines.

Schaub, M., Gereke, J., & Baldassarri, D. (2020). Does Poverty Undermine Cooperation in Multiethnic Settings? Evidence from a Cooperative Investment Experiment.

Cambridge University Press, Journal of Experimental Political Science, 1-14. Jul 2019
What undermines cooperation in ethnically diverse communities? Scholars have focused on factors that explain the lack of inter-ethnic cooperation, such as prejudice or the difficulty to communicate and sanction across group boundaries. We direct attention to the fact that diverse communities are also often poor and ask whether poverty, rather than diversity, reduces cooperation. We developed a strategic cooperation game where we vary the income and racial identity of the interaction partner. We find that beliefs about how poor people behave have clear detrimental effects on cooperation: cooperation is lower when people are paired with low-income partners, and the effect is particularly strong when low-income people interact among themselves. We observe additional discrimination along racial lines when the interaction partner is poor. These findings imply that poverty and rising inequality may be a serious threat to social cohesion, especially under conditions of high socioeconomic segregation.

Gereke J, Schaub M, Baldassarri D (2018) Ethnic diversity, poverty and social trust in Germany: Evidence from a behavioral measure of trust.

PLoS ONE 13(7): e0199834. Jul 2018
Several scholars have concluded that ethnic diversity has negative consequences for social trust. However, recent research has called into question whether ethnic diversity per se has detrimental effects, or whether lower levels of trust in diverse communities simply reflect a higher concentration of less trusting groups, such as poor people, minorities, or immigrants. Drawing upon a nationally representative sample of the German population (GSOEP), we make two contributions to this debate. First, we examine how ethnic diversity at the neighborhood level–specifically the proportion of immigrants in the neighborhood–is linked to social trust focusing on the compositional effect of poverty. Second, in contrast to the majority of current research on ethnic diversity, we use a behavioral measure of trust in combination with fine-grained (zip-code level) contextual measures of ethnic composition and poverty. Furthermore, we are also able to compare the behavioral measure to a standard attitudinal trust question. We find that household poverty partially accounts for lower levels of trust, and that after controlling for income, German and non-German respondents are equally trusting. However, being surrounded by neighbors with immigrant background is also associated with lower levels of social trust.

Publications

Baldassarri, Delia, Gereke, Johanna, and Schaub, Max (2024) Prosociality Beyond In-Group Boundaries: A Lab-in-the-Field Experiment on Selection and Intergroup Interactions in a Multiethnic European Metropolis

Sociological Science 11: 815-853. Sep 2024
How does prosocial behavior extend beyond in-group boundaries in multiethnic societies? The differentiation of Western societies presents an opportunity to understand the tension between societal pressures that push people outside the comfort zones of their familiar networks to constructively interact with unknown diverse others and the tendency toward homophily and in-group favoritism. We introduce a three-step model of out-group exposure that includes macrostructural conditions for intergroup encounters and microlevel dynamics of intergroup selection and interaction. Using lab-in-the-field experiments with a large representative sample of Italian natives and immigrants from the multiethnic city of Milan, we find that, when pushed to interact with non-coethnics, Italians generally treat them similarly to how they treat coethnics and value signs of social and market integration. However, when given the opportunity to select their interaction partners, Italians favor coethnics over immigrants. Taken together, these results help reconcile classical findings concerning the positive effects of intergroup contact with evidence documenting the persistence of out-group discrimination in selection processes.

Hellyer, Joshua, and Gereke, Johanna (2024) The shadow of fear: hate crime victimization and stress after Charlottesville

Frontiers in psychology, 15: 1384470 Jun 2024
Recent years have witnessed an increase in highly publicized attacks against members of minority groups. To date, scholarship has primarily focused on the tendency for such trigger events to generate violent aftershocks. However, we hypothesize that trigger events create a climate of fear that may also significantly impact minorities’ mental health and well-being. To test our conjuncture, we draw upon both national survey data as well as federal hate crime data in combination with a natural experiment involving the Unite the Right rally and vehicle attack in Charlottesville, Virginia. We first show that there was an increase in anti-Black hate crimes in the two weeks following Charlottesville. We also link the Charlottesville attack to an increase in stress about personal hate crime victimization among African-Americans. Interestingly, these results are confined to African-Americans, suggesting that both violent aftershocks and the general climate of fear may be racially bounded.

Kretschmer, David, Gereke, Johanna, Winter, Fabian and Zhang, Nan (2023) No differential effects of classroom ethnic composition on native and immigrant friendship segregation: Comment on Smith et al., 2016

American Journal of Sociology, Volume 129 Number 2 (September 2023): 570-585 Nov 2023
What is the relationship between classroom ethnic composition and patterns of ethnic friendship segregation amongst native and immigrant adolescents? In a 2016 AJS article, Smith et al. analyzed data on adolescents’ friendship networks from four European countries and found differential effects of classroom composition on natives’ and immigrants’ friendship choices. In this comment, we identify estimation problems in a large number of classroom networks included in Smith et al.’s original study. We demonstrate that immigrant homophily cannot be meaningfully estimated in many networks containing insufficient numbers of immigrant students from the same ethnic group. After accounting for these estimation problems at the network level, our re-analyis provides little evidence that classroom composition has differential effects for native and immigrant homophily.

Hellyer, Joshua, Hellriegel, Emily, Gereke, Johanna and Schunck, Reinhard (2023) Pretty unequal? Immigrant-native differences in returns to physical attractiveness in Germany

Journal of Economic Behavior & Organization, 2023:215, pp.107-119 Sep 2023
How do the economic returns to physical attractiveness vary between immigrants and natives? Despite a growing literature on the beauty premium, previous scholarship has not examined whether the size of this premium might vary according to immigrant status, an important axis of social stratification in European societies. We study this question in the German labor market using longitudinal data from a large, randomly drawn nationwide sample that includes interviewer ratings of respondents’ physical attractiveness. Results from a multiverse analysis provide strong evidence of a beauty premium for native German men and women. However, we find mixed results for ethnic minority groups. These results highlight how perceived physical attractiveness is linked to labor market stratification.

Gereke, Johanna and Ruedin, Didier (2023) Trusting and Reciprocating Trust of Citizens versus Non-Citizens: Experimental Evidence from the U.S., South Africa and Switzerland

Socius: sociological Research for a Dynamic World Aug 2023
We examine how trust and trustworthiness varies with the citizenship status of the alter in three democratic countries with varying sharres of immigrants and levels of economic development: the United States, South Africa, and Switzerland. Trust games were implemented in representative surveys. While we find significant differences in overall levels of trust and trustworthiness across countries, we do not find any significant differences in the degree to which participants trusted or reciprocated trust of interaction partners with the same vs. foreign citizenship status in any of the three countries. Our results suggest that citizenship status is not a salient identity marker to shape trust or trustworthiness in these types of interpersonal interactions.

Auer, D., Gereke,J and Schaub M (2023) Spiritual practices predict migration behavior

Scientific reports Aug 2023
Each year, several thousand migrants from Sub-Saharan Africa die attempting to reach Europe’s southern shores. Social scientists and policymakers have been puzzling over the question why so many people are prepared to take this extremely high risk of dying. Drawing on panel data from over 10,000 individuals in The Gambia, one of the countries with the highest emigration rates in the world, we show that cultural beliefs in terms of spiritual practices are strongly associated with a decreased perception of one’s own risk of dying on the migration journey. We find that consulting a healer for spiritual protection predicts migration plans and actual migration behavior.

Gereke, Johanna, et al. (2022) Demographic Change and Group Boundaries in Germany: The Effect of Projected Demographic Decline on Perceptions of Who Has a Migration Background

Sociological Science 9, 206-220 May 2022
In many Western societies, the current “native” majority will become a numerical minority sometime within the next century. How does prospective demographic change affect existing group boundaries? An influential recent article by Abascal (2020) showed that white Americans under demographic threat reacted with boundary contraction—that is, they were less likely to classify ambiguously white people as “white.” The present study examines the generalizability of these findings beyond the American context. Specifically, we test whether informing Germans about the projected decline of the “native” population without migration background affects the classification of phenotypically ambiguous individuals. Our results show that information about demographic change neither affects the definition of group boundaries nor generates negative feelings toward minority outgroups. These findings point to the relevance of contextual differences in shaping the conditions under which demographic change triggers group threat and boundary shifts..

N. Zhang, J. Gereke, D. Baldassarri (2022) Everyday Discrimination in Public Spaces: A Field Experiment in the Milan Metro

European Sociological Review, 38.5: 679-693 Feb 2022
A large scholarship documents discrimination against immigrants and ethnic minorities in institutional settings such as labour and housing markets in Europe. We know less, however, about discrimination in informal and unstructured everyday encounters. To address this gap, we report results from a large-scale field experiment examining the physical avoidance of immigrants as an unobtrusive yet important measure of everyday discrimination in a multiethnic European metropolis. In addition to varying confederates’ migration background and race, we also vary signals of status (business versus casual attire) in order to shed light on the mechanisms underlying discriminatory patterns. We find that natives are averse to contact with Nigerian confederates, but do not discriminate against Chinese confederates. Furthermore, manipulating confederates’ attire has little effect on natives’ behaviour. Overall, our results highlight the everyday burdens borne particularly by individuals of African descent in commonplace, ‘street-level’ encounters.

J. Gereke, M. Schaub, D. Baldassarri (2022). Immigration, integration and cooperation: experimental evidence from a public goods game in Italy

Journal of Ethnic and Migration Studies, 48(15), 3761-3788 Jul 2021
Immigration has rapidly changed the demographic profile of most Western European societies, increasing their ethnic diversity. Some cross-disciplinary literature comparing homogeneous and diverse communities provides observational evidence of a link between high levels of ethnoracial diversity and lower levels of public goods provision. While these results are often interpreted as driven by context/interaction effects, whereby individuals lower their cooperativeness in response to the presence of non-coethnics, they could also be explained by composition effects – immigrants having different baseline levels of cooperativeness, and thereby lowering average cooperation rates. To disentangle these effects, we conducted a lab-in-the-field experiment with a sample of Italians and immigrants from Morocco and the Philippines residing in Milan. In our public goods experiment, participants were randomly assigned to either homogeneous or ethnically mixed groups. We find that Italians behave similarly in both homogeneous and heterogeneous groups, thus contradicting arguments about the negative effects of diversity on the native population, while there are both compositional and interactional effects when considering the behaviour of Moroccan and Filipino immigrants, respectively. Moreover, differences largely disappear when we consider only the behaviour of more socio-economically integrated immigrants, highlighting the need for a more processual understanding of cooperation in multiethnic communities.

M. Schaub, J. Gereke, D. Baldassarri (2021). Strangers in Hostile Lands: Exposure to Refugees and Right-wing Support

Comparative Political Studies, 54(3-4), 686-717 Sep 2020
Does local exposure to refugees affect right-wing support and anti-immigrant sentiments? This paper studies the allocation of refugees to the rural hinterlands of Eastern Germany during the refugee crisis of 2015. Similar to non-urban regions elsewhere, the area has seen a major shift towards the political right, despite minimal previous exposure to foreigners. We draw on electoral records and original data collected among 1,320 German citizens from 236 municipalities, half of which received refugees. Two conditions allow for causal identification: a policy allocating refugees following strict administrative rules, and a matching procedure rendering treated and control municipalities statistically indistinguishable. Our survey and behavioral measures confirm the presence of widespread anti-immigrant sentiments, but these are entirely unaffected by the presence of refugees in respondents’ hometowns. If anything, local exposure to refugees served as a ‘reality check’, pulling both right- and left-leaning individuals more towards the center.

J. Gereke, M. Schaub, D. Baldassarri. Gendered discrimination against immigrants: experimental evidence

Frontiers in Sociology, 5, 59. Sep 2020
Recent migration from Muslim-majority countries has sparked discussions across Europe about the supposed threat posed by new immigrants. Young men make up the largest share of newly arrived immigrants and this demographic is often perceived to be particularly threatening. In this article, we compare pro-sociality and trust towards immigrants from Muslim-majority countries, focusing on gender differences in treatment. We study these questions using behavioral games that measure strategic (trusting) and non-strategic (pro-social) behavior. Our data comes from measures embedded in a large survey of residents of Germany’s eastern regions, where anti-immigrant sentiments are high. We find that Germans are similarly pro-social toward immigrant men and women in non-strategic situations, but are significantly less likely to trust immigrant men (but not women) in strategic encounters. These findings provide evidence that immigrants’ gender can be an important factor conditioning the behavior of the majority population, but also caution that (gendered) ethnic discrimination may be situationally dependent. Future research should further examine the exact mechanisms underlying this variation in discriminatory behavior.

Gereke, J., & Gërxhani, K. Experimental Economics and Experimental Sociology

Oxford research encyclopedia: economics and finance. Nov 2019
Experimental economics has moved beyond the traditional focus on market mechanisms and the “invisible hand” by applying sociological and socio-psychological knowledge in the study of rationality, markets, and efficiency. This knowledge includes social preferences, social norms, and cross-cultural variation in motivations. In turn, the renewed in­ terest in causation, social mechanisms, and middle-range theories in sociology has led to a renaissance of research employing experimental methods. This includes laboratory experiments but also a wide range of field experiments with diverse samples and settings. By focusing on a set of research topics that have proven to be of substantive interest to both disciplines—cooperation in social dilemmas, trust and trustworthiness, and social norms—this article highlights innovative interdisciplinary research that connects experimental economics with experimental sociology. Experimental economics and experimental sociology can still learn much from each other, providing economists and sociologists with an opportunity to collaborate and advance knowledge on a range of underexplored topics of interest to both disciplines.

Schaub, M., Gereke, J., & Baldassarri, D. (2020). Does Poverty Undermine Cooperation in Multiethnic Settings? Evidence from a Cooperative Investment Experiment.

Cambridge University Press, Journal of Experimental Political Science, 1-14. Jul 2019
What undermines cooperation in ethnically diverse communities? Scholars have focused on factors that explain the lack of inter-ethnic cooperation, such as prejudice or the difficulty to communicate and sanction across group boundaries. We direct attention to the fact that diverse communities are also often poor and ask whether poverty, rather than diversity, reduces cooperation. We developed a strategic cooperation game where we vary the income and racial identity of the interaction partner. We find that beliefs about how poor people behave have clear detrimental effects on cooperation: cooperation is lower when people are paired with low-income partners, and the effect is particularly strong when low-income people interact among themselves. We observe additional discrimination along racial lines when the interaction partner is poor. These findings imply that poverty and rising inequality may be a serious threat to social cohesion, especially under conditions of high socioeconomic segregation.

Gereke J, Schaub M, Baldassarri D (2018) Ethnic diversity, poverty and social trust in Germany: Evidence from a behavioral measure of trust.

PLoS ONE 13(7): e0199834. Jul 2018
Several scholars have concluded that ethnic diversity has negative consequences for social trust. However, recent research has called into question whether ethnic diversity per se has detrimental effects, or whether lower levels of trust in diverse communities simply reflect a higher concentration of less trusting groups, such as poor people, minorities, or immigrants. Drawing upon a nationally representative sample of the German population (GSOEP), we make two contributions to this debate. First, we examine how ethnic diversity at the neighborhood level–specifically the proportion of immigrants in the neighborhood–is linked to social trust focusing on the compositional effect of poverty. Second, in contrast to the majority of current research on ethnic diversity, we use a behavioral measure of trust in combination with fine-grained (zip-code level) contextual measures of ethnic composition and poverty. Furthermore, we are also able to compare the behavioral measure to a standard attitudinal trust question. We find that household poverty partially accounts for lower levels of trust, and that after controlling for income, German and non-German respondents are equally trusting. However, being surrounded by neighbors with immigrant background is also associated with lower levels of social trust.

Teaching

 
 
 
 
 

Interim Professor

Johannes Gutenberg University Mianz

Apr 2023 – Feb 2024 Mainz, Germany
 
 
 
 
 

Workshop Instructor

German Institute for Global and Area Studies (GIGA)

Oct 2019 – Oct 2019 Hamburg, Germany
 
 
 
 
 

Research Fellow

Mannheim Centre for European Social Research

Feb 2019 – Present Mannheim, Germany
 
 
 
 
 

Instructor Global Study Program

University of Cologne

Mar 2018 – Jul 2018 Cologne, Germany
 
 
 
 
 

Instructor

Heinrich-Heine University

Jun 2016 – Jul 2016 Düsseldorf, Germany
 
 
 
 
 

Teaching Assistant

European University Institute

Jan 2015 – Mar 2016 Florence, Italy

Skills

STATA

Qualtrics

LaTeX

OTree

German

native

English

fluent

French

intermediate

Italian

basic

Contact