Published papers

Threat and parochialism in intergroup relations: lab-in-the-field evidence from rural Georgia. 2017. Proceedings of the Royal Society B 284 (1865):20171560. Link to article. Manuscript. Press coverage (Science Magazine).

Competition between groups is widely considered to foster cooperation within groups. Evidence from lab experiments hints at the existence of a proximate mechanism by which humans increase their level of support for their ingroup when faced with an external threat. Further work suggests that ingroup support should go along with aggressive behaviour towards the outgroup, although these theories are at odds with others that see high investments in outgroup relations as important means of stabilising inter-group relations. Surprisingly few of these arguments have been tested in the field, however, and existing studies are also limited by the lack of a direct measure of threat perception and aggressive behaviour. This study presents lab-in-the-field results from a rural context where exposure to an ethnic outgroup varies between villages. This context makes it possible to capture levels of threat perception, aggressive behaviour and cooperation without having to induce intergroup competition artificially in the lab. All concepts are measured behaviourally. Ingroup and outgroup cooperation was measured with a standard public goods game, and a novel experimental protocol was developed that measures both perceived threat and aggressive behaviour: the threat game. The results show that levels of perceived threat, ingroup cooperation and aggressive behaviour are higher in regions more strongly exposed to ethnic outsiders. However, exposed regions also show high levels of outgroup cooperation and a concomitant lack of elevated ingroup bias. This pattern is explained by theorising that communities show parochial altruism when faced with an ethnic outgroup, but balance aggressive behaviour with cooperative offers to diffuse tensions and to keep open channels of mutually beneficial exchange.

Second-order ethnic diversity: the spatial pattern of diversity, competition and cooperation in Africa. 2017. Political Geography 59 (July): 103–16. Link to article. Manuscript.

Ethnic diversity has been linked to important social outcomes such as economic underperformance and civil war, yet its study is still hampered by conceptual difficulties and imprecise measurement. In this paper, a modified understanding of ethnic diversity is developed. Ethnic diversity is disaggregated into two components—first- and second-order ethnic diversity—which have opposing consequences for collective outcomes. While first-order ethnic diversity—the diversity of a local community—is theorized to undermine cooperation, second-order ethnic diversity—the ethnic diversity of the hinterland of a community—is theorized to induce ethnic competition, thereby reinforcing cooperation. Relating data from over 100,000 individuals interviewed at 2,942 locations in 33 African countries to novel subnational indicators of first- and second-order ethno-linguistic diversity, the theory is tested and its basic tenets confirmed. In a next step, I show that it is indeed ethnic competition that accounts for the positive association between second-order diversity and increased cooperation: second-order ethnic diversity is a much better predictor of cooperation in regions where contemporary or historical factors have exacerbated interethnic tensions. The paper sheds new light on the debate on the consequences of ethnic diversity for cooperation and contributes to our understanding of the origins of the global ‘geography of social capital’.

The redistributive impact of hypocrisy in international taxation. 2017. Regulation & Governance 10.1111/rego.12156 (with L. Hakelberg). Link to article.

Why do tax havens, whose attractiveness for foreign capital depends on financial secrecy, agree to automatically report account data to foreign governments? From a contractualist perspective, their cooperation should be motivated by the expectation of joint gains. Prior to agreeing, however, tax havens had expected outflows of foreign capital and reductions in economic activity as likely outcomes. We show that the U.S. imposed automatic information exchange on these countries without itself participating. The result is a strongly redistributive regime that worsens the economic situation of tax havens. By means of a difference-in-differences analysis, we ascertain a substantial and statistically significant negative effect of a U.S. sanctions threat on the value of assets held by foreigners in tax havens relative to non-havens. The effect becomes stronger when the U.S. is included in the non-haven group. The analysis confirms the U.S.’s ability to redistribute financial wealth internationally through organized hypocrisy.

Cross-cultural regularities in the cognitive architecture of pride. 2017. Proceedings of the National Academy of Sciences, 114(8), 1874–1879 (with D. Sznycer, Al-Shawaf, L., Bereby-Meyer, Y., Curry, O. S., De Smet, D., Ermer, E., Kim, S., Kim, S., Li, N. P., Lopez Seal, M. F., McClung, J., O, J., Ohtsubo, Y., Quillien, T., Sell, A., van Leeuwen, F., Cosmides, L., & Tooby, J.). Link to article.

Pride occurs in every known culture, appears early in development, is reliably triggered by achievements and formidability, and causes a characteristic display that is recognized everywhere. Here, we evaluate the theory that pride evolved to guide decisions relevant to pursuing actions that enhance valuation and respect for a person in the minds of others. By hypothesis, pride is a neurocomputational program tailored by selection to orchestrate cognition and behavior in the service of: (i) motivating the cost-effective pursuit of courses of action that would increase others’ valuations and respect of the individual, (ii) motivating the advertisement of acts or characteristics whose recognition by others would lead them to enhance their evaluations of the individual, and (iii) mobilizing the individual to take advantage of the resulting enhanced social landscape. To modulate how much to invest in actions that might lead to enhanced evaluations by others, the pride system must forecast the magnitude of the evaluations the action would evoke in the audience and calibrate its activation proportionally. We tested this prediction in 16 countries across 4 continents (n = 2,085), for 25 acts and traits. As predicted, the pride intensity for a given act or trait closely tracks the valuations of audiences, local (mean r = +0.82) and foreign (mean r = +0.75). This relationship is specific to pride and does not generalize to other positive emotions that coactivate with pride but lack its audience-recalibrating function.

Lines Across the Desert: Mobile Phone Use and Mobility in the Context of trans-Saharan Migration. 2012. Information Technology for Development 18, no. 2: 126–144. Article.

In West and Northern Africa, mobile phone coverage has been expanding in parallel to increased attempts by Africans to migrate overland to Europe. This paper explores possible links between the two phenomena, looking specifically into the role of mobile phones in trans-Saharan migration. It provides a first detailed description of the telecommunication processes underlying contemporary trans-Saharan migration. An analytical framework is presented that helps to explain how mobile phones facilitate migration by interacting with the social and spatial factors shaping migrants’ mobility. By drawing on this framework and fieldwork conducted among Congolese migrants in Morocco, it is shown that the expansion of the communication infrastructure is, on the one hand, only one of several factors that have turned the region into a more “transitable” space. On the other hand, the use of mobile phones is demonstrated to be central to the migration process: migrants draw on the unprecedented accessibility of contacts equipped with mobile phones to tie together novel, geographically expansive networks. Phones are also shown to be used by migrants’ ‘helpers’ for the purpose of internal coordination.

Working papers and work in progress

Ethnic Riots and Pro-Social Behavior: Evidence from Kyrgyzstan. Revise & resubmit, American Political Science Review (with K. Krakowski and A. Rink).

Do ethnic riots affect pro-social behavior? A common view among scholars of ethnic violence is that riots increase cooperation within the warring groups, while cooperation across groups is reduced. We revisit this hypothesis by studying the aftermath of the 2010 Osh riot, which saw Kyrgyz from outside the city kill over 400 Uzbeks. We implement a pre-registered representative survey, which includes unobtrusive experimental measures of pro-social behavior. Our causal identification strategy exploits variation in the distance of neighborhoods to armored military vehicles, which were instrumental in orchestrating the riot. Our results demonstrate that damaged neighborhoods show substantially lower levels of pro-social behavior. Importantly, using a within-subjects design, we demonstrate that the reduction is isomorphic within and across groups. We discuss several potential mechanisms and point to social disintegration as the most likely channel. We confirm the robustness of our findings using a variety of permutation and falsification tests.

Income and racial discrimination in a strategic cooperation dilemma. 2017. Revise & resubmit, Journal of Experimental Political Science (with D. Baldassarri and J. Gereke). Pre-registration document.

Ethnically diverse communities are often found to have lower levels of solidarity and cooperation than homogeneous communities. However, ethnically diverse communities are usually also poor communities, and it is not clear whether racial diversity rather than diffused poverty may undermine their cooperative capacity. In our project we study how prosocial behavior is affected by the ethnicity and economic status of alters, and test a few hypotheses concerning how ethnic bias and expectations about alter’s strategic behavior affect prosocial behavior. We developed a cooperative investment game in which the optimal outcome is only realized when the two partners cooperate, and payouts are only made after two weeks. We will employ this measure to test for differences in cooperation in a pool of participants recruited on Amazon Mechanical Turk (N = 1,200). The participants will engage in the cooperation task with an interaction partner whose identity varies along racial (white or black) and income (earning 10,000– 20,000$/year or 60,001– 80,000$/year) lines. This design will allow us to compare cooperative behavior toward low-income Blacks, low-income Whites, high-income Blacks, and high-income Whites. We will also measure altruistic behavior using a standard dictator game, and will record demographic and income data. These additional measures will allow us to assess whether discriminatory behavior is due to ethnic bias or strategic considerations about alter’s behavior, and to analyze results for subgroups of participants.

Populist mobilization in the echo chamber: identifying the causal effect of internet use on support for populist parties. Work in Progress (with D. Morisi).

A natural experiment in outgroup exposure: Eastern Germany during the refugee crisis of 2015. Work in Progress (with J. Gereke and D. Baldassarri).

Solidarity with a sharp edge: communal conflict and local collective action in rural Nigeria, HiCN Working Paper no. 183, September 2014, and Afrobarometer Working Paper no. 149, December 2014. Working paper.

This paper provides new insights into the link between the experience of violent conflict and local collective action. I use the temporal and geographical information from four rounds of survey data from Nigeria to relate measures of cooperation to past and future incidences of communal conflict. I show that local collective action, measured in terms of community meeting attendance and volunteering, is highest before the outbreak of violence—higher than both post-conflict levels and the generally lower levels of cooperation in regions not affected by violence. I develop a mobilization mechanism to explain these findings, arguing that, rather than being an indicator of social capital, collective action ahead of communal violence is inherently ambiguous, and driven by a form of situationally adaptive (and potentially aggressive) 'solidarity with an edge'. I further show that the positive link between previous exposure to civil war-type violence and cooperation holds for a range of other countries in Africa, too, but is restricted to rural areas only.

Mobile phone access and migration: evidence from the expansion of mobile phone coverage in Latin America. Work in progress.

Policy documents
Humanitarian problems relating to migration in the Turkish-Greek border region: the crucial role of civil society organisations. March 2013. Research Resources Paper, COMPAS, University of Oxford.

The European Union—Republic of Moldova Mobility Partnership 2008-2011: Evaluation Report. October 2012.

Selected conference presentations and invited talks

‘Altruism, cooperation and right-wing support in the presence of newcomers: Eastern Germany after the refugee crisis’, paper presented at conference Migrant Integration in Africa, Europe, and Beyond, Berlin, 23-24 February 2018.

‘Community relations in the aftermath of violence: evidence from the 2010 riots in Osh, Kyrgyzstan’, IPI Brown Bag Seminar, WZB, 27 November 2017.

‘Second-order ethnic diversity: the spatial pattern of diversity, competition and cooperation in Africa’, paper presented at the 7th EPSA Annual Conference, Milan, 22–24 June 2017.

‘Poverty, ethnic diversity and cooperation – theory and early results from an online experiment’, invited talk at the Wissenschaftszentrum (WZB) Berlin, 2 November 2016.

‘Using lab-in-the-field behavioural games for hypothesis testing: threat and cooperation in rural Georgia’, paper presented at the CRRC’s 4th Methodological Conference, Tbilisi, 24–25 June 2016.

‘Outgroup threat and ingroup cooperation: field evidence’, invited talk at the Spanish National Research Council, Madrid, 12 May 2016.

‘Does ethnic diversity undermine or foster cooperation? The ethnic diversity of the hinterland and its implications for community cooperation in Africa’, MPSA Annual Conference, Chicago, 7–10 April 2016.

‘Ethnic competition and community cooperation: experimental evidence from rural Georgia’, invited talk at the Wissenschaftszentrum (WZB) Berlin, 9 December 2015.

‘The violent origins of trustworthiness?’ invited talk for the seminar ‘Foundations of Social Life: Trust and Trustworthiness’ organized by Prof. Diego Gambetta, European University Institute, 17 February 2015.

‘War and cooperativeness in rural Nigeria’, paper presented at the EPSA Annual Conference, Edinburgh, 19–21 June 2014.