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In Coethnicity: Diversity and the Dilemmas of Collective Action, James Habyarimana, Macartan Humphreys, Daniel N Posner and Jeremy M Weinstein discuss the potential mechanisms through which diversity can harm voluntary collective action. The book presents key results from a long-term research program in Kampala, Uganda (some of which has been previously published in peer-reviewed journals). Using a variety of survey and experimental methods, the authors argue that the key causal mechanism for diversity’s negative influence on collective action stems from the inability of diverse groups to effectively sanction non-contributors across ethnic boundaries. A brief description of each chapter will be provided below, followed by final comments on their work.
The first chapter discusses the prior literature motivating this project, namely an extensive series of studies establishing a negative relationship between diversity and successful collective action in a wide variety of settings. The authors then further describe the target communities, discuss their sampling design, and establish that the negative relationship between diversity and successful collective action holds for these communities. The second chapter extends the description of these communities by providing detailed backgrounds for each and additional information regarding the current state of public good provision in this area. Focus groups supplement the large-scale survey data by describing the state of repair for these public goods and to whom the responsibility falls for their maintenance.
The third chapter focuses on a discussion of how we, as scholars or individuals, define ethnicity. Importantly, these two definitions may not coincide. The authors then discuss the ability of individuals to accurately identify the ethnicity of others. While participants in the authors’ sample were substantially better at identifying coethnics than non-coethnics, identifiability was far from perfect. Patterns of misidentification are thus analyzed. The fourth chapter presents the experimental design and information treatment. Three key mechanisms are tested within the environment: Preference Mechanisms (regarding people, goods, or process), for which no supporting evidence is found; Technology Mechanisms (efficacy, ‘readability’, frequency of interactions, social networks and ‘reachability’), for which mixed evidence exists; and Strategy Selection (specifically reciprocity), for which they find strong support. Attempts to interpret the evidence are unable to fully distinguish the causal mechanism since some support was found for both technology and strategy selection channels.
Since the empirics support two different mechanisms (Technology and Strategy Selection), the authors focus on disentangling competing explanations in Chapter 5. To do this, they draw on a new analysis of their previous results and new results from a Prisoner’s Dilemma game with sanctioning. They find that generous (non-egoists in their terminology) types of people do not condition their behavior on ethnicity on how observable their actions are. Selfish (egoists) individuals on the other hand condition their responses otherwise. Further, when a third party has the ability to impose sanctions, the egoists cooperate at high levels with both coethnics and non-coethnics. The authors take this as evidence that either the coethnics-specific or the universal norm may be active, depending on the strategic context. In observable interactions the coethnic reciprocity norm governs the interaction. But, if you have both observability and proper enforcement via appropriate sanctions, then cooperation can be sustained across ethnic lines. This indicates that the causal mechanism is Strategy Selection and that the negative effects of diversity can be traced to the inability of heterogeneous groups to effectively and appropriately apply sanctions across ethnic boundaries.
To attempt to extend the validity of their results to a broader area, the authors examine in Chapter 6 the participants’ understanding and interpretations of the game, correlations between behavior in the games and choices outside of the lab. They survey community leaders to get on-the-ground impressions of the causes of collective action failures as well as descriptions of collective action successes. They find that most successes occur when an ethnic group provides services to coethnics or when a small number of individuals value a service enough that they are willing to provide it to the whole community all on their own. Chapter 7 concludes and highlights the importance of institutions.
Coethnicity presents an interesting discussion for readers with some background experience in the topic. While very readable for a broad audience, the book presents only a brief review of the relevant reference literature in favor of presenting their research design, results, and analysis. The research agenda undertaken by the authors is thoughtful and intriguing. Designing useful public policies requires an understanding of the causal mechanisms underlying behavior, and the authors have completed a very comprehensive study to flesh out these mechanisms. One of the great contributions of this work is the thoughtful research design for field experiments.
As with any study, there are several shortcomings. The design assumes that individuals will similarly react in larger group settings as they do in dyads (used here), ignoring potential impacts from being in the ethnic majority or other dominant group. Likewise, group dynamics, the role of leadership, and broader strategies (other than reciprocity) are not considered. Certainly these are reasonable design choices when undertaking such an ambitious research program, but they are also key aspects in how communities function, and need to be considered by policy makers before applying the insights from this research. Further, this discussion does not address the broader problems (such as the perceived justness of sanctioning, determining what the appropriate sanction should be, and concerns regarding racial profiling or vigilante justice) that may arise if these sanctions are implemented. These present interesting avenues of research for the next generation of diversity scholars.
