Stephen Robert Assistant Professor of Political Science
Brown University
I am a scholar of comparative politics at Brown University. My research bridges the study of political institutions and intergroup relations to address the twin challenges of representation and inclusion in diverse democratic societies, primarily in Africa. In AY 2025–2026, I am on academic leave at MIT and Georgetown.
Prior to Brown, I was faculty at the University of Pittsburgh and a Postdoctoral Fellow at the University of Pennsylvania. I received my PhD in Political Science from UC Berkeley and a BA in economics with highest honors from Korea University.
Research
Published — Princeton University Press (2022)
Princeton Studies in Political Behavior
Donghyun Danny Choi, Mathias Poertner, and Nicholas Sambanis
An examination of the roots and remedies of discrimination against Muslim immigrants in Europe, demonstrating how shared civic norms and identities can overcome deep-seated bias.
In the aftermath of the refugee crisis caused by conflicts in the Middle East and an increase in migration to Europe, European nations have witnessed a surge in discrimination targeted at immigrant minorities. To quell these conflicts, some governments have resorted to the adoption of coercive assimilation polices aimed at erasing differences between natives and immigrants. Are these policies the best method for reducing hostilities? Native Bias challenges the premise of such regulations by making the case for a civic integration model, based on shared social ideas defining the concept and practice of citizenship. Drawing from original surveys, survey experiments, and novel field experiments, Donghyun Danny Choi, Mathias Poertner, and Nicholas Sambanis show that although prejudice against immigrants is often driven by differences in traits such as appearance and religious practice, the suppression of such differences does not constitute the only path to integration. Instead, the authors demonstrate that similarities in ideas and value systems can serve as the foundation for a common identity, based on a shared concept of citizenship, overcoming the perceived social distance between native and immigrants. Addressing one of the most pressing challenges of our time, Native Bias offers an original framework for understanding anti-immigrant discrimination and the processes through which it can be overcome.
“This is a terrific book—one of the best I’ve read in a long time. Polished, theoretically sophisticated, and logically structured, it brings to bear new evidence and approaches on a critical contemporary topic.” — Daniel N. Posner, UCLA
“This excellent book addresses one of the most important issues of our time: how to overcome the discrimination of immigrants and, ultimately, how to secure their successful integration into new societies.” — Peter Thisted Dinesen, University of Copenhagen
“Native Bias offers a compelling and hopeful analysis of the challenges facing countries grappling with increasing cultural diversity. Indispensable reading for anyone interested in immigrant integration and multicultural politics!” — Rafaela M. Dancygier, Princeton University
Best Book Award, Experimental Research Section, American Political Science Association 2023
Under Contract — Cambridge University Press
Cambridge Studies in Comparative Politics
Donghyun Danny Choi
A study of how political parties systematically break the link between voters and their representatives, showing how leaders trade off local responsiveness for internal control through the high-stakes logic of the nomination contest.
Juan Linz Prize for Best Dissertation in the Study of Democracy, American Political Science Association 2020
Opposition victories after periods of democratic erosion are commonly portrayed as turning points that can help restore democracy. This essay argues that this optimism is often misplaced. An analysis of more than 40 elections in Africa since 1990 in which an opposition candidate defeated an autocratizing incumbent reveals that democracy stagnated or declined in half these cases. The authors attribute this pattern to two mutually reinforcing mechanisms inherited from the previous era of democratic erosion. First, new leaders inherit a landscape of weakened institutions — pliant legislatures, politicized courts, and captured state agencies — which are far easier to exploit for their own political consolidation than to rebuild. Second, years of repression teach opposition elites which legal and coercive strategies are most effective for ensuring political survival. This “opposition learning” encourages them to use, rather than dismantle, these authoritarian instruments once they are in power. Through detailed case studies of recent opposition victories in Malawi and Zambia, the authors illustrate how these dynamics operate in practice. Despite celebrated electoral turnovers, these new governments began to repurpose the tools of their predecessors, engaging in judicial manipulation, selective prosecutions, and the cooptation of state power. This combination of institutional inheritance and learned repression often transforms a celebrated alternation of power into a “smarter autocracy,” illustrating why electoral turnover by itself is seldom sufficient to guarantee democratic recovery.
Overcoming America’s deep partisan polarization poses a unique challenge: Ameri-cans must be able to sharply disagree on who should govern while agreeing onmore fundamental democratic principles. We study one model of depolarization—reciprocal group reflection—inspired by marital counseling and implemented bya non-partisan non-governmental organization, Braver Angels. We randomly as-signed undergraduates at four universities either to participate in a Braver Angelsworkshop or simply to complete three rounds of surveys. The workshops substan-tially reduced polarization according to explicit and implicit measures. They alsoincreased participants’ willingness to donate to programs aimed at depolarizingpolitical conversations. These effects are consistent across partisan groups, thoughsome dissipate over time. Using qualitative data, and building on contact and delib-erative theories, we argue that depolarization is especially effective when it includesboth informational and emotional components, such that citizens who are moved toempathize with outgroup members become more likely to internalize new informa-tion about them.
When are politicians willing to liberalize abortion laws? While restricted access to legal abortion affects millions of women around the world, there is relatively little understanding of the factors shaping the views of politicians who craft or uphold such restrictive laws. This study examines the impact of a public health framing commonly employed by activists to persuade politicians to reform abortion laws. We provide evidence that politicians’ preferences toward abortion reforms are shaped by the intersection of gender and wealth. Drawing on a survey experiment conducted among more than 600 politicians in Zambia, we show that only women politicians from less wealthy backgrounds are more likely to support policy liberalization after being exposed to a public health framing. These findings underscore how economic inequalities can affect the substantive representation of women’s interests and provide a baseline for further research on the use of framing strategies in other developing country contexts.
Why do native Europeans discriminate against Muslim immigrants? Can shared ideas between natives and immigrants reduce discrimination? We hypothesize that natives’ bias against Muslim immigrants is shaped by the belief that Muslims hold conservative attitudes about women’s rights and this ideational basis for discrimination is more pronounced among native women. We test this hypothesis in a large-scale field experiment conducted in 25 cities across Germany, during which 3,797 unknowing bystanders were exposed to brief social encounters with confederates who revealed their ideas regarding gender roles. We find significant discrimination against Muslim women, but this discrimination is eliminated when Muslim women signal that they hold progressive gender attitudes. Through an implicit association test and a followup survey among German adults, we further confirm the centrality of ideational stereotypes in structuring opposition to Muslims. Our findings have important implications for reducing conflict between native–immigrant communities in an era of increased cross-border migration.
High temperatures have been linked to aggression and different forms of conflict in humans. We consider whether exposure to heat waves increases discriminatory behavior toward outgroups. Using data from two large-scale field experiments in Germany, we find a direct causal effect of exposure to heat shocks on discrimination in helping behavior. As temperature rises, German natives faced with a choice to provide help to strangers in every-day interactions help Muslim immigrants less than they do other German natives, while help rates toward natives are unaffected by temperature. This finding suggests that there may be a physiological basis for discriminatory behavior toward outgroups.
Can endorsements persuade voters to transcend politicized identity cleavages to support candidates from other groups? We argue that the persuasive power of cleavage-bridging endorsements depends on the ability of politicians to elicit ingroup trust on behalf of out-group candidates. The activation of in-group trust increases the likelihood of voting for out-group candidates by changing both instrumental and affective assessments about the nature of the voter-candidate relationship. To assess these claims, we provide evidence from Kenya, where simulated radio news segments experimentally manipulated the ethnic relationship among voters, endorsers, and candidates. We find that voters who hear endorsements from in-group politicians are significantly more likely to vote for out-group candidates and view them as trustworthy. We further find that the trust premium transferred from in-group endorsers to out-group candidates leads voters to regard them as nondiscriminatory representatives who care about their well-being.
How does a researcher's identity shape the design, implementation, and interpretation of field experiments? This wip draws on the collective experiences of five researchers who have conducted field experiments across diverse settings to reflect on the practical and ethical implications of insider and outsider positionality. The authors provide recommendations for navigating these dynamics while maintaining research integrity.
Understanding sources of judicial bias is essential for establishing due process. To date, theories of judicial decision making are rooted in ranked societies with majority–minority group cleavages, leaving unanswered which groups are more prone to express bias and whether it is motivated by in-group favoritism or out-group hostility. We examine judicial bias in Kenya, a diverse society that features a more complex ethnic landscape. While research in comparative and African politics emphasizes instrumental motivations underpinning ethnic identity, we examine the psychological, implicit biases driving judicial outcomes. Using data from Kenyan criminal appeals and the conditional random assignment of judges to cases, we show that judges are 3 to 5 percentage points more likely to grant coethnic appeals than non-coethnic appeals. To understand mechanisms, we use word embeddings to analyze the sentiment of written judgments. Judges use more trust-related terms writing for coethnics, suggesting that in-group favoritism motivates coethnic bias in this context.
Party switching among legislative candidates has important implications for accountability and representation in democratizing countries. We argue that party switching is influenced by campaign costs tied to the clientelistic politics that persist in many such countries. Candidates who are expected to personally pay for their campaigns, including handouts for voters, will seek to affiliate with parties that can lower those costs through personal inducements and organizational support. Campaign costs also drive candidate selection among party leaders, as they seek to recruit candidates who can finance their own campaigns. We corroborate these expectations with an original survey and embedded choice experiment conducted among parliamentary candidates in Zambia. The conjoint analysis shows that candidates prefer larger parties that offer particularistic benefits. The survey further reveals that parties select for business owners as candidates—the very candidates most likely to defect from one party to another.
What explains discrimination against immigrants and what can reduce it? Using a large-scale field experiment conducted across 28 German cities, this study measures the behavioral foundations of anti-immigrant discrimination and tests whether a shared civic identity can counteract it. The results show that parochial norms drive native residents to discriminate against immigrants, but that priming a common civic identity significantly reduces discriminatory behavior.
Ingroup bias and outgroup prejudice are pervasive features of human behavior, motivating various forms of discrimination and conflict. In an era of increased cross-border migration, these tendencies exacerbate intergroup conflict between native populations and immigrant groups, raising the question of how conflict can be overcome. We address this question through a large-scale field intervention conducted in 28 cities across three German states, designed to measure assistance provided to immigrants during everyday social interactions. This randomized trial found that cultural integration signaled through shared social norms mitigates—but does not eliminate—bias against immigrants driven by perceptions of religious differences. Our results suggest that eliminating or suppressing ascriptive (e.g., ethnic) differences is not a necessary path to conflict reduction in multicultural societies; rather, achieving a shared understanding of civic behavior can form the basis of cooperation.
Scholars have increasingly turned to fuzzy set Qualitative Comparative Analysis (fsQCA) to conduct smalland medium-N studies, arguing that it combines the most desired elements of variable-oriented and caseoriented research. This wip demonstrates, however, that fsQCA is an extraordinarily sensitive method whose results are worryingly susceptible to minor parametric and model specification changes. We make two specific claims. First, the causal conditions identified by fsQCA as being sufficient for an outcome to occur are highly contingent upon the values of several key parameters selected by the user. Second, fsQCA results are subject to marked confirmation bias. Given its tendency toward finding complex connections between variables, the method is highly likely to identify as sufficient for an outcome causal combinations containing even randomly generated variables. To support these arguments, we replicate three wips utilizing fsQCA and conduct sensitivity analyses and Monte Carlo simulations to assess the impact of small changes in parameter values and the method’s built-in confirmation bias on the overall conclusions about sufficient conditions.
Does greater descriptive representation of women lead to more substantive attention to women’s concerns in legislatures? Existing studies showing that women legislators prioritize gendered issues have been limited by underdeveloped theoretical accounts of how such advocacy emerges and by causal evidence that hinges on legal mandates that simultaneously alter electoral incentives and institutional enforcement, making it difficult to isolate the independent effect of women’s presence from these confounding factors. We propose a theoretical framework that emphasizes interpersonal peer dynamics—the daily interactions among legislators that ultimately shape policy agendas. We argue that exposure to women peers in legislative committees increases attention to women’s issues through social learning, norm diffusion, and role model activation. We test this argument using quasi-random variation in the gender composition of standing committees in South Korea’s National Assembly, a legislature without binding gender quotas. Drawing on 1.8 million speeches (2000–2024) and 5,000 campaign manifestos (2008–2024), we measure women’s issue advocacy using dictionary and large language model (LLM) classifiers. We find that legislators, regardless of gender, become more vocal on women-related concerns after serving alongside more women in legislative committees. These effects extend to plenary sessions and campaign platforms. Our findings show that descriptive representation can foster substantive representation through everyday peer exposure even in the absence of institutional mandates.
How does the repression of opposition leaders outside of parliament affect legislative behavior within it? Prior research emphasizes the effects of repression on mobilization, protest, and elections, but few works examine its consequences on legislative debate. We argue that in democratic contexts where dissent is normally allowed and encouraged, opposition repression has a chilling effect on opposition speech-making because it generates uncertainty over both the bounds of permissible speech and the consequences of speaking beyond these bounds. We explore these dynamics in Zambia during the presidency of Edgar Lungu, when the opposition leader Hakainde Hichilema was suddenly and arbitrarily arrested on charges of sedition and treason. Using data on more than 350,000 parliamentary speeches from the Zambian National Assembly between 2011-2021, we leverage a difference-in-differences design to compare parliamentary speech patterns of opposition and incumbent party legislators before and after the arrest of the opposition leader. We find a marked deterioration in the quantity and quality of debate following the arrest, including persistent reductions in the frequency and length of speeches made by opposition legislators as well as their discussion of substantive policy issues. We further show that opposition legislators were more likely to be interrupted during their speaking turn and denied requests to speak by the House Speaker, which we interpret as increased incivility by incumbent party members towards opposition members. Our findings demonstrate the pernicious consequences of repression on freedom of speech and democratic representation in new democracies.
Are cross-cleavage campaigns effective in polarized societies? While social demographics and electoral rules in many countries compel candidates to pursue votes outside their own identity groups, the efficacy of such campaigns remains unclear in polarized contexts. We argue that cross-cleavage electoral outreach through in-person campaign rallies can inadvertently trigger inter-group differentiation and competition, resulting in the heightened salience of identity and depressed voter support for outgroup candidates. We assess these claims by exploiting the timing of an unscheduled campaign rally held by an outgroup presidential candidate in another ethnic group’s stronghold during Kenya’s 2017 election. Comparing survey respondents before and after the rally, we find that the outgroup candidate’s post-rally favorability significantly decreased among ingroup voters, while the proportion of voters identifying in ethnic terms simultaneously increased. These findings contribute to a more nuanced understanding of the challenges faced in democratic elections in socially divided societies.
Although women have entered government in African countries at an unprecedented rate over the past three decades, it remains unknown to what extent they have acquired the influence necessary to shape policymaking. Are women able to exercise personal influence to the same degree or in the same ways as their male counterparts? We argue that women tend to be less influential than men due to the structure of their personal networks with other politicians. Prior scholarship on African politics has demonstrated that political outcomes depend on the personal ties that connect politicians to one other. Based on a novel network survey among Zambian candidates, we demonstrate that women tend to be peripherally situated within networks. We find that women are systematically less likely to be connected to others in social or work networks among politicians. We also demonstrate that, while having fewer connections than men, women have connections with more important people in both social and work networks.
We investigate whether transient exposure to refugees can durably affect native attitudes and behavior. Our case is Greece’s refugee crisis, which saw a sudden influx of more than 1 million refugees in 2015 following the escalation of conflicts in the Middle East. We capitalize on the fact that the Aegean Islands—the epicenter of the refugee crisis—are home to the campus for the University of the Aegean (UA), which draws students from across Greece. We conduct a targeted survey (N=3,900) of student cohorts that attended university prior to or during the refugee crisis. Employing an instrumented difference-in-difference design and a matching strategy informed by distinctive features of the Greek university admissions system, we compare the current-day attitudes, preferences, and behavioral dispositions of students who attended the University of the Aegean and thereby had significant exposure to refugees during the crisis, to otherwise similar students who attended university elsewhere and thus had limited exposure. Our findings paint a more complex picture than existing work; students who attended UA during the crisis have more favorable attitudinal and behavioral dispositions towards refugees today, but also simultaneously support more restrictive immigration policy.
When are politicians willing to extend formal social protections to LGBT+ minorities? While the protection of civil liberties and rights for LGBT+ communities continues to feature prominently in political debates around the world, there is limited understanding of the factors that shape the views of politicians who enact the laws that govern these protections. This study examines the effectiveness of two competing frames—that cast the protection of LGBT+ individuals either as a public health crisis or a human rights crisis—that advocacy organizations frequently employ to persuade policymakers to liberalize their position on LGBT+ minority protection. Drawing on a survey and experiment conducted among more than 600 political candidates who contested for national and local office in Zambia, we show that politicians are significantly more likely to respond to the human rights frame than the public health frame. These effects are primarily driven by male candidates and exist only when the crisis is explicitly framed in terms of its impact on the general public rather than the LGBT+ communities themselves. An analysis of open-ended responses provides suggestive evidence regarding the mechanism underlying these effects; the human rights frame appears to have reduced politicians’ tendency to dehumanize members of the LGBT+ community.
Whether foreign aid is captured by domestic political favoritism may depend critically on the donor's organizational form. This paper investigates this proposition by comparing aid projects from bilateral (China, United States) and multilateral (World Bank, African Development Bank) donors across Sub-Saharan Africa, asking if partisan alignment between a legislator and the national executive causally shifts project placement. To isolate the effect of political favoritism, we implement a close-election regression discontinuity design on a new panel linking geocoded aid projects to constituency-level election results. The results reveal a sharp asymmetry between the two donor types. We find that constituencies that narrowly elect a legislator from the ruling party see a 7--10 percentage point increase in the probability of receiving a bilateral donor aid project. This effect operates on the extensive margin-whether a constituency receives its first project-ather than on the number of projects. In contrast, we find no evidence that partisan alignment affects the allocation of multilateral donor rojects. Our findings suggest that the institutional design of donors is a key mediating factor in the politics of aid: while the discretion afforded by bilateral aid channels allows for domestic political capture, the procedures of multilateral institutions appear to insulate aid from this form of constituency-level favoritism.
Why do pro-climate policies in democracies often fail to have the impacts environmentalists expect? In the context of the United States, we argue that the Biden administration’s 2021 clean energy policy surge activated a strategic weaponization of local energy politics. Local opposition to wind and solar energy occurs in both Republican- and Democratic-leaning areas, but the pattern has changed since 2021. We theorize that political opponents mobilized against renewable energy projects specifically in electorally competitive states, aiming to simultaneously undermine the Democratic coalition for clean energy and instrumentalize this opposition for electoral gain. We test this hypothesis by analyzing the county-level adoption of restrictive renewable energy ordinances and project rejections, employing a difference-in-differences design and a novel dataset of over 3,000 U.S. counties from 2010 to 2023. We find that while resistance also occurs in Republican and Democratic strongholds, the post-2021 growth in opposition was disproportionately concentrated in counties within electorally competitive states. Our findings are consistent with the proposition that local energy politics were weaponized in the contest for national political power.
Teaching
Quantitative Research Methods IV: Replication
Graduate, Brown University
Quantitative Research Methods II
Graduate, Brown University
Contemporary African Politics (Lecture)
Undergraduate, Brown University
Introduction to Comparative Politics (Lecture)
Undergraduate, Brown University
Identity Politics in Global Perspective (Seminar)
Undergraduate, Brown University
Computational Social Science (Lecture)
Undergraduate, University of Pittsburgh
Prospectus Seminar I & II
Graduate, University of Pittsburgh