Working papers

Antisocial behavior in groups. (with Jana Cahlíková, D.Celik-Katreniak, J. Chytilová, L. Cingl, T. Želinský), 2017.

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The Effets of Poverty on Impatience: Preferences or Inattention? (with V. Bartoš, J. Chytilová and I. Levely), 2018.

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Published or forthcoming papers

War Increase Religiosity. (with A. Cassar, J. Chytilova, J. Henrich, B.G. Purzycki), 2019, Nature Human Behavior.
Does the experience of war increase people’s religiosity? Much evidence supports the idea that particular religious beliefs and ritual forms can galvanize social solidarity and motivate in-group cooperation, thus facilitating a wide range of cooperative behaviours including—but not limited to—peaceful resistance and collective aggression. However, little work has focused on whether violent conflict, in turn, might fuel greater religious participation. Here, we analyse survey data from 1,709 individuals in three post-conflict societies—Uganda, Sierra Leone and Tajikistan. The nature of these conflicts allows us to infer, and statistically verify, that individuals were quasirandomly afflicted with different intensities of war experience—thus potentially providing a natural experiment. We then show that those with greater exposure to these wars were more likely to participate in Christian or Muslim religious groups and rituals, even several years after the conflict. The results are robust to a wide range of control variables and statistical checks and hold even when we compare only individuals from the same communities, ethnic groups and religions.

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Social Contagion of Ethnic Hostility(with J. Cahlíková, J. Chytilová and T. Želinský).PNAS, 2018, 115 (15): 4881-4886.
Inter-ethnic conflicts often escalate rapidly. Why does the behavior of masses easily change from cooperation to aggression? This paper provides the experimental test of whether group-based hostility is contagious. Using incentivized tasks, we measure willingness to sacrifice one’s own resources to harm others among adolescents from a region with a history of violence against the Roma people, the largest ethnic minority in Europe. To identify the influence of peers, subjects make choices after observing either destructive or peaceful behavior of peers in the same task. We find that susceptibility to follow destructive behavior more than doubles when harm targets Roma instead of co-ethnics. When peers are peaceful, subjects do not discriminate. We observe very similar patterns in a norms elicitation experiment: destructive behavior towards Roma is not generally rated as more socially appropriate than when directed at co-ethnics but norms are more sensitive to social contexts. The findings illuminate why ethnic hostilities can spread quickly, even in societies with few visible signs of inter-ethnic hatred.

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Trusting Former Rebels: An Experimental Approach to Understanding Reintegration after Civil War(with I. Levely and N. Fiala). Economic Journal, 2018, 128:1786-1819.
We use a set of experiments to study the effects of forced military service for a rebel group on social capital. We examine the case of Northern Uganda, where recruits did not self-select nor were systematically screened by rebels. We find that individual cooperativeness robustly increases with length of soldiering, especially among those who soldiered during early age. Parents of ex-soldiers are aware of the behavioral difference: they trust ex-soldiers more and expect them to be more trustworthy. These results suggest that the impact of child soldiering on social capital, in contrast to human capital, is not necessarily detrimental.

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Can War Foster Cooperation?(with C. Blattman, J. Chytilova, J. Henrich, E. Miguel and T. Mitts). Journal of Economic Perspectives, 2016, 30(3): 249-74.
In the past decade, nearly 20 studies have found a strong, persistent pattern in surveys and behavioral experiments from over 40 countries: individual exposure to war violence tends to increase social cooperation at the local level, including community participation and prosocial behavior. Thus while war has many negative legacies for individuals and societies, it appears to leave a positive legacy in terms of local cooperation and civic engagement. We discuss, synthesize and reanalyze the emerging body of evidence, and weigh alternative explanations. There is some indication that war violence especially enhances in-group or “parochial” norms and preferences, a finding that, if true, suggests that the rising social cohesion we document need not promote broader peace.

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Attention Discrimination: Theory and Field Experiments with Monitoring Information Acquisition. (with: V. Bartoš, J. Chytilová and F. Matejka). American Economic Review, 2016, 106(6): 1437-75.
We integrate tools to monitor information acquisition in correspondence field experiments and examine whether discrimination arises already when decision-makers choose effort to read an application. In both countries we study, negatively stereotyped minority names reduce employers’ effort to inspect resumes of applicants. In contrast, minority names increase information acquisition in the rental housing market. Both results are consistent with a model of rational allocation of costly attention, which magnifies the role of prior beliefs beyond the one considered in the standard model of statistical discrimination. The findings have implications for magnitude of discrimination, returns to human capital and policy.

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War's enduring effects on the development of egalitarian motivations and in-group biases (with A. Cassar, J. Chytilová and J. Henrich), Psychological Science, 2014, 25(1): 47-57.
In suggesting that new nations often coalesce in the decades following war, historians have posed an important psychological question: does the experience of war generate an enduring elevation in people’s egalitarian motivations toward their in-group? We administered social choice tasks to over a thousand children and adults differentially affected by wars in the Republic of Georgia and Sierra Leone. We find that greater exposure to war creates a lasting increase in egalitarian motivations towards one’s in-group, but not out-groups, during a developmental window that starts in middle childhood (~7 years) and ends in early adulthood (~20 years). Outside this window, war has no measurable impacts on social motivations in young children, and only muted effects on older adults. While “war effects” are broadly consistent with predictions from evolutionary approaches that emphasize the importance of group cooperation against external threats, they also highlight key areas in need of greater theoretical development.

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> Protocol Research brief(eng)Research brief(cz)>
Seminar talk (video) Interview at Radio Cesko(cz)


Parental Background and Other-regarding Preferences in Children (with J. Chytilová, B. Pertold-Gebicka), Experimental Economics, 2014, 17(1): 24-46.
Other-regarding preferences are important for establishing and maintaining cooperative outcomes. In this paper, we study how the formation of other-regarding preferences during childhood is related to parental background. Our subjects, aged 4–12 years, are classified into other-regarding types based on simple binary-choice dictator games. The main finding is that the children of parents with low education are less altruistic, more selfish, and more likely to be weakly spiteful. This link is robust to controlling for a rich set of children’s characteristics and class fixed effects. It also stands out against the overall development of preferences, as we find children to become more altruistic, less selfish, and less likely to be weakly spiteful with increasing age. The results, supported by a complementary analysis of World Values Survey data, suggest an important role of socialization in the formation of other-regarding preferences.

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Women, Children and Patience: Experimental Evidence from Rural India (with J. Chytilová), Review of Development Economics, 2013, 14(4): 662-675.
In this paper we study the link between women’s responsibility for children and their preferences. We use a large random sample of individuals living in rural India, incentive compatible measures of patience and risk aversion, and detailed survey data. We find more patient choices among women who have a higher number of children. The age of children matters: The link with patience is specific for children below 18 years old, and the highest level of patience is associated with having three children. We do not observe this link among men. Taken together, we find significant gender differences in patience that are predicted by a higher number of children. The results are robust to controlling for age, education, income constraints, and individual and location characteristics. These findings suggest an important context when the spending preferences of spouses diverge, and support the view that empowering women in developing countries should lead to more future-oriented choices of households.

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Behavioral Foundations of Microcredit: Experimental and Survey Evidence from Rural India (with J. Chytilová and J. Morduch). American Economic Review, 2012, 102(2): 1118-1139.
We use experimental measures of time discounting and risk aversion for villagers in south India to highlight behavioral features of microcredit, a financial tool designed to reduce poverty and fix credit market imperfections. The evidence suggests that microcredit contracts may do more than reduce moral hazard and adverse selection by imposing new forms of discipline on borrowers. We find that, conditional on borrowing from any source, women with present-biased preferences are more likely than others to borrow through microcredit institutions. Another particular contribution of microcredit may thus be to provide helpful structure for borrowers seeking self-discipline.

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OnlineAppendix> TEDxPrague video (cz) Research brief(eng) Research brief(cz)


The Impact of Education on the Subjective Discount Rate in Ugandan Villages. (with J. Chytilová). Economic Development and Cultural Change, 2010, 58 (4), 643–669
Heterogeneity in time discounting may reinforce the existing barriers to save and invest faced by rural populations in developing countries. We elicit a subjective discount rate for a varied sample of Ugandan villagers. In accordance with other studies, we have found the discount rate to decrease with education. We examine this correlation further by testing the causal effect of education and exploit two different sources of its variation: school frequency across villages and the number of the respondents' school-going years that overlap with the era of the dictator Idi Amin's rule. For men, we find that education has a significant impact on their discount rate, similar in magnitude for both types of instruments and robust to observable characteristics. This finding highlights the importance of education in development.

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