We partnered with an ayahuasca center in Brazil to study the well-being effects of a one-time ayahuasca treatment within a ritualized group setting. The center enrolled 429 first-time ayahuasca users to participate in the largest randomized controlled trial of psychedelics ever run. Relative to placebo, ayahuasca increases happiness and reduces psychological distress six months later by roughly 0.4 standard deviations. The field experimental setting allows investigation of aspects not explored in the large clinical literature. Positive effects are almost entirely driven by participants who were distressed at baseline. Improvements in well-being are strongly positively correlated with the mystical nature of trips. The mystical experience can also be induced by placebo with ritual, though less frequently, and when done so induces a similar magnitude of well-being improvement. Effects are larger for older people, consistent with the idea that psychedelics reopen a window of heightened malleability. We estimate the mental health benefits of participating in an ayahuasca ceremony to be roughly 200 times the cost of 24 USD.

We ran a non-randomized market-level experiment in Kolkata vegetable markets in which we subsidized vendors in some markets to sell additional produce. The vendors earned over 60% higher profits, excluding the value of the subsidy. Nevertheless, after the subsidy ended many vendors stopped selling the additional produce. Vendors had knowledge of the profitable opportunity and demonstrated that they were capable of exploiting it without assistance. We conclude that their behavior meaningfully diverges from profit maximization when considering take-home pay, likely due to some combination of high costs of effort at the margin, and perceived sanctions from breaking anti-competitive norms.

We study whether tweets about racial justice predict costly related behaviors. Academics that tweet about racial justice are more likely to favor minority students in an audit experiment, receive higher teaching ratings, work with more Black co-authors, and are more likely to subsequently leave Twitter. Non-academics that tweet about racial justice make larger private donations towards racial justice efforts. However, three pieces of evidence suggest that higher returns to tweeting reduce the predictive value of racial justice tweets. First, tweets became almost completely uninformative during the aftermath of the murder of George Floyd, when more people were tweeting about racial justice. Second, the informativeness of tweets is driven by low-visibility tweet types, like retweets. Third, racial justice retweets are somewhat less informative of donation behavior than private statements of support. Finally, we find that roughly half of surveyed graduate students are overly cynical, believing tweets to be close to uninformative.

Many group identities that influence economic behavior are imperfectly observed. Individuals and institutions often conceal identity markers to limit discrimination. Yet concealment also creates uncertainty about group membership, hampering coordination in social interaction. To study this tradeoff, we paired high- and low-caste men for collaborative data entry work in North India. We randomly assigned each mixed-caste pair to either be: (i) introduced by full names, making caste common knowledge; (ii) introduced by first names only, making caste disclosure a choice; or (iii) instructed not to disclose caste. The two concealment conditions substantially reduce the accuracy of beliefs about a partner’s caste and confidence in those beliefs. They also weaken workplace relations, lowering trust, willingness to interact, and perceived productivity—consistent with identity helping structure social coordination. Evidence on mechanisms shows that identity concealment inhibits authentic interaction, making workers less able to express their “true selves,” while certainty about a partner’s identity is associated with stronger workplace ties. Concealment leaves a sizable caste disparity in higher-status role assignment intact, suggesting minimal impacts on discrimination. We conclude that where group identities are socially entrenched, reducing their legibility may undermine intergroup relations.

We hypothesize that broad contact, involving brief interactions with multiple outgroup members, and deep contact, meaning longer interactions with a single outgroup member, play distinct roles in shaping intergroup relations. We set up a factory in India and recruited Hindu and Muslim men to work in pairs on joint production tasks. We randomly assigned participants to work either with the same ingroup or outgroup partner daily (deep contact), a different outgroup partner each day (broad contact), or to a control group. Deep contact strengthens social and economic ties with the outgroup partner interacted with, but leads to more polarized beliefs about outgroup strangers. Only broad contact reduces misperceptions about outgroup strangers. These findings align with a model in which independent sampling (observing multiple outgroup members) promotes learning about outgroups more than prolonged interaction with a single individual does. Nevertheless, neither type of contact changes behavior toward the wider outgroup.

State sponsorship of religion has theoretically ambiguous effects. Financial support can increase religious participation by funding proselytization efforts, or reduce clergy effort by stifling competition and limiting accountability. We study these forces in eighteenth-century Britain using a natural experiment. During a period that saw the rapid rise of non-state ("dissenting") sects, the state issued lottery-based grants of land to support poor state clergy through a program called Queen Anne’s Bounty. Winning a grant increased clergy income by 80% initially, with this effect converging to 5% 30 years later, as lottery-losers eventually won grants themselves. Winning parishes were less likely to report the presence of dissenting households in the short term, and less likely to construct dissenting churches in the long term, yet score lower on a composite index of religious service provision. We provide evidence that this latter channel lowers overall religious participation. Our results support a hypothesis going back to Adam Smith that by limiting competition in the marketplace of ideas, state sponsorship of religion can negatively affect religious life.

Cultural beliefs usually evolve slowly, but during times of religious revival, beliefs change rapidly. During the two-year Welsh Revival of 1904-5, roughly 6% of the adult population converted to Christianity, after decades of stable religiosity. This religious shock was temporary, with church membership returning to pre-Revival levels five years later. I report three main findings. First, church growth during the Revival was higher in areas with more crime and more mining industry. Second, comparing Wales with neighboring England, the Revival led to a reduction in aggregate crime by 15%. The crime reduction is concentrated among violent crime, and drunkenness, considered a major social ill at the time. Third, despite temporary effects of the Revival on church membership, effects on crime persist, suggesting an enduring shift in social norms. Collectively, these results provide support for Fogel’s theory of America’s Great Awakenings: social crisis predicts religious revival and revival brings social change.

Joint household decision-making becomes more common as economies develop. Can external intervention advance this transition? We study this question in the context of female employment in India. We randomized which spouse was given a ticket enabling enrollment in a women's weaving job, and cross-randomized the other to receive no information about the ticket, information, or information and discussion with their spouse. Academic and local experts predict information and discussion should raise enrollment. Instead, information had no effect, and discussion reduced enrollment by 50%. We do not find an effect of giving the wife the job ticket rather than the husband. Our results show that intervention towards joint decision-making about an opportunity can lower take-up.

Weekly lotteries determine which politicians ask the UK Prime Minister a question in front of a male-dominated, noisy chamber. Lottery winners receive 4% higher vote margin in the next election, but women are 12% less likely to submit questions than same-cohort men. The gender gap does not close with lottery-induced experience asking a question, but it closes after a format change, with questions asked to a smaller, quieter audience. The switch differentially draws in women with quieter voices. Our findings support institutional change, rather than experience, as a response to gender gaps in adversarial settings like the UK Parliament.

We randomized mobile money transfers to a sample of low-income Ghanaians during the COVID-19 pandemic. Treated households received eight transfers that sum to roughly one month's income, while control households only received one transfer. The mere announcement of upcoming transfers has null effects. Once disbursed, transfers increase contemporaneous food expenditure by 8% and income by 20%, but do not affect psychological well-being. Over 40% of the transfers are spent on food. We find suggestive evidence that transfers increased social distancing. The positive effect on income does not persist to two years after the last transfer, and surprisingly, two-year effects on consumption and psychological well-being are negative. Together, we learn that pandemic-era cash transfers can support households economically without diminishing adherence to public health protocols, though with null or negative long-term effects.

Non-family-based institutions for socializing young people may play a vital role in creating close-knit, inclusive communities. We study the potential for youth camps—integrating rituals, sports, and civics training—to strengthen intergroup cohesion. We randomly assigned Hindu and Muslim adolescent boys, from West Bengal, India, to two-week camps or to a pure control arm. To isolate mechanisms, we cross-randomized collective rituals (such as singing the national anthem, wearing uniforms, chanting support during matches, and synchronous dancing) and the intensity of intergroup contact. We find that camps reduce ingroup bias, increase willingness to interact with outgroup members, and enhance psychological well-being. Campers continue to have twice as many outgroup friends as control participants one year after the camps ended. Meanwhile, additional camp elements have heterogeneous effects: rituals have more positive impacts for the Hindu majority than the Muslim minority, while higher intergroup contact backfires among Hindus but not Muslims. Our findings demonstrate that inclusive youth camps may be a powerful tool for bridging deep social divides. Yet, we also highlight the conceptual challenges in crafting optimal integrative camps that help all groups.

Intergroup contact is arguably the prejudice-reduction intervention with the most existing empirical support. However, recent meta-analyses of experimental contact interventions find signs of publication and reporting biases. To mitigate such bias, I carry out a meta-analysis of 41 pre-registered contact experiments, considering only treatment effects on pre-registered primary outcomes. I find that (i) the average effects of intergroup contact are smaller than previous findings, at roughly one-tenth of a standard deviation, (ii) the subset of in-person interventions that satisfy Allport’s four desirable scope conditions (e.g. common goals) are no more effective, and (iii) “generalization” is limited—contact is more effective at changing behavior and attitudes towards people met than toward the outgroup as a whole. I offer suggestions for how researchers might make progress on this problem of generalization, through careful measurement of the extent of generalization, and the consideration of moderating factors beyond those emphasized by Allport.

Nearly all legislatures segregate politicians by party. We use seating lotteries in the Icelandic Parliament to estimate the effects of seating integration on bipartisanship. When two MPs from different parties are randomly assigned to sit together, they are roughly 0.5 to 1 percentage points more likely to vote alike. This limited peer influence is only robust in the case of voting on contested bills. In a survey of past and present MPs, most respondents doubt the possibility of peer influence. Exploring dynamics, we find that neighbor influence is temporary, disappearing the following year. These results support cue-taking and social pressure as likely mechanisms for the small effect of other-party proximity on voting. Finally, we find suggestive evidence that seating proximity builds weak ties, through co-sponsorship, despite the lack of persistent effects on voting.

I estimate the effects of collaborative and adversarial intergroup contact. I randomly assigned Indian men from different castes to participate in cricket leagues or to serve as a control group. League players faced variation in collaborative contact, through random assignment to homogeneous-caste or mixed-caste teams, and adversarial contact, through random assignment of opponents. Collaborative contact increases cross-caste friendships and efficiency in trade, and reduces own-caste favoritism. In contrast, adversarial contact generally reduces cross-caste interaction and efficiency. League participation reduces intergroup differences, suggesting that the positive aspects of intergroup contact more than offset the negative aspects in this setting.

We document the impact of India’s COVID-19 lockdown on the food supply chain. Food arrivals in wholesale markets dropped by 69% in the three weeks following the lockdown and wholesale prices rose by 8%. Six weeks after the lockdown began, volumes and prices had fully recovered. The initial food supply shock was highly correlated with early incidence of COVID-19. We provide evidence that this correlation is due more to state-level lockdown policy variation than local responses of those in the food supply chain. Finally, during the recovery phase, the correlation between the food supply disruption and COVID-19 exposure disappeared, suggesting uniform recovery.

Why does capital not flow to developing countries as predicted by the neoclassical model? What are the direction and degree of capital misallocation across nations? We revisit these questions by removing public capital from total capital to achieve a more accurate estimate of the marginal productivity of private capital. We calculate marginal product of capital schedules in a large sample of advanced and developing countries. Our main result is that, in terms of the Lucas Paradox, private capital is allocated remarkably efficiently across nations. Tentative estimates of the marginal productivity of public capital suggest that the deadweight loss from public capital misallocation across countries can be much larger than that from private capital.

Are newly created identities capable of supplanting traditional group attachments in places with entrenched social divisions? Many organizations, from state militaries to scouting movements, have attempted to advance social integration by encouraging individuals to identify with groups that cut across existing ethnic, gender, and religious lines. Yet, few studies rigorously assess the effectiveness of such efforts outside controlled laboratory settings or other artificial environments. We examine a recategorization approach to intergroup relations using a large-scale randomized evaluation of a House System implemented in 176 middle and secondary schools in Tamil Nadu, India. Half of the schools were randomly assigned to split students into four mixed Houses, bringing together children from different genders and social backgrounds; schools organized a range of academic, athletic, and extracurricular activities around these new affiliations. Twenty months after the system's introduction, we measured its impacts on identity formation, friendship networks, school climate, and outgroup attitudes, through surveys of 2,455 students. The intervention successfully generated awareness of—and attachment to—House identities among students, demonstrating that institutions are capable of cultivating new forms of collective belonging. At the same time, estimated effects on all downstream outcomes are small and statistically indistinguishable from zero. Overall, our results suggest that newly forged identities can coexist with longstanding group loyalties without replacing them, underscoring the limits of recategorization as a tool for building social cohesion in naturalistic settings.

Despite being illegal for over 50 years, caste-based untouchability practices remain pervasive in modern India. These discriminatory norms prevent over 200 million people from accessing basic economic activities and public services and perpetuate economic inequality. Human Rights Watch refers to this as a "hidden" apartheid, underscoring the lack of systematic data on untouchability. We address this gap by (i) digitizing historical data on untouchability practices from large-scale surveys conducted 20-50 years ago, (ii) conducting contemporary surveys in previously-surveyed villages to establish a panel of how discriminatory practices have changed over time, and (iii) fielding observational and lab-in-the-field measures of modern untouchability. We will use these data to document the persistence and transformation of these practices, as well as conduct causal analyses on what economic and social policies shape discriminatory norms.