Ethnically homogenous communities often do a better job than diverse communities of producing public goods such as satisfactory schools and health care, adequate sanitation, and low levels of crime. Coethnicity reports the results of a landmark study that aimed to find out why diversity has this cooperation-undermining effect. The study, conducted in a neighborhood of Kampala, Uganda, notable for both its high levels of diversity and low levels of public goods provision, hones in on the mechanisms that might account for the difficulties diverse societies often face in trying to act collectively.

The Mulago-Kyebando Community Study uses behavioral games to explore how the ethnicity of the person with whom one is interacting shapes social behavior. Hundreds of local participants interacted with various partners in laboratory games simulating real-life decisions involving the allocation of money and the completion of joint tasks. Many of the subsequent findings debunk long-standing explanations for diversity's adverse effects. Contrary to the prevalent notion that shared preferences facilitate ethnic collective action, differences in goals and priorities among participants were not found to be structured along ethnic lines. Nor was there evidence that subjects favored the welfare of their coethnics over that of non-coethnics. When given the opportunity to act altruistically, individuals did not choose to benefit coethnics disproportionately when their actions were anonymous. Yet when anonymity was removed, subjects behaved very differently. With their actions publicly observed, subjects gave significantly more to coethnics, expected their partners to reciprocate, and expected that they would be sanctioned for a failure to cooperate. This effect was most pronounced among individuals who were otherwise least likely to cooperate. These results suggest that what may look like ethnic favoritism is, in fact, a set of reciprocity norms--stronger among coethnics than among non-coethnics--that make it possible for members of more homogeneous communities to take risks, invest, and cooperate without the fear of getting cheated. Such norms may be more subject to change than deeply held ethnic antipathies--a powerful finding for policymakers seeking to design social institutions in diverse societies.

Research on ethnic diversity typically draws on either experimental research or field work. Coethnicity does both. By taking the crucial step from observation to experimentation, this study marks a major breakthrough in the study of ethnic diversity.

A large and growing literature links high levels of ethnic diversity to low levels of public goods provision. Yet although the empirical connection between ethnic heterogeneity and the underprovision of public goods is widely accepted, there is little consensus on the specific mechanisms through which this relationship operates. We identify three families of mechanisms that link diversity to public goods provision — what we term “preferences,” “technology,” and “strategy selection” mechanisms — and run a series of experimental games that permit us to compare the explanatory power of distinct mechanisms within each of these three families.

Results from games conducted with a random sample of 300 subjects from a slum neighborhood of Kampala, Uganda, suggest that successful public goods provision in homogenous ethnic communities can be attributed to a strategy selection mechanism: in similar settings, co-ethnics play cooperative equilibria, whereas non-co-ethnics do not. In addition, we find evidence for a technology mechanism: co-ethnics are more closely linked on social networks and thus plausibly better able to support cooperation through the threat of social sanction. We find no evidence for prominent preference mechanisms that emphasize the commonality of tastes within ethnic groups or a greater degree of altruism toward co-ethnics, and only weak evidence for technology mechanisms that focus on the impact of shared ethnicity on the productivity of teams.

Some rebel groups abuse noncombatant populations, while others exhibit restraint. Insurgent leaders in some countries transform local structures of government, while others simply extract resources for their own benefit. In some contexts, groups kill their victims selectively, while in other environments violence appears indiscriminate, even random. This book presents a theory that accounts for the different strategies pursued by rebel groups in civil war, explaining why patterns of insurgent violence vary so much across conflicts. It does so by examining the membership, structure, and behavior of four insurgent movements in Uganda, Mozambique, and Peru. Drawing on interviews with nearly 200 combatants and civilians who experienced violence firsthand, it shows that rebels' strategies depend in important ways on how difficult it is to launch a rebellion. The book thus demonstrates how characteristics of the environment in which rebellions emerge constrain rebel organization and shape the patterns of violence that civilians experience.

How does the resource base of a rebel group impact its membership, structure, and behavior? While scholars, analysts, and policy makers increasingly link natural resources to the onset and duration of civil war, this article explores how resource endowments shape the character and conduct of rebel groups. This article identifies a rebel "resource curse" much like the one that undermines state institutions in resource-rich environments. While the presence of economic endowments makes it possible for leaders to recruit on the basis of short-term rewards, these groups are flooded with opportunistic joiners who exhibit little commitment to the long-term goals of the organization. In resource-poor environments, leaders attract new recruits by drawing on social ties to make credible promises about the private rewards that will come with victory. Opportunistic joiners stay away from these movements, leaving a pool of activist recruits willing to invest their time and energy in the hope of reaping large gains in the future.

The war in the Democratic Republic of the Congo (DRC), which began in August 1998, is unprecedented-at times involving armies from eight African states. Soldiers from Chad are fighting alongside regiments from Namibia, Angola, and Zimbabwe in defense of President Laurent Kabila. And on offense, the two main rebel groups, the Congolese Assembly for Democracy (which is known by the acronym RCD) and the Movement for the Liberation of Congo (MLC), are backed by troops from Uganda and Rwanda. As Susan E. Rice, assistant secretary of state for African affairs, warned the House International Relations Committee in September 1998, "The fighting threatens regional stability, hampers economic progress, endangers the lives of millions of people, perpetuates human rights abuses, and impedes the democratic transformation of Africa's third-largest country." This war, Rice said, is potentially "among the most dangerous conflicts on the globe."

Yet, the war in Congo goes on almost unnoticed outside of Africa. While African heads of state spent much of the last year shuttling across the continent, wrestling with the crisis and searching for a peaceful solution, Congo has been largely missing from the agendas of the Western powers and multilateral organizations. Only in January, when the U.S. representative to the United Nations, Richard Holbrooke, taking advantage of his tenure as Security Council president to draw attention to Africa, did the war enter Western consciousness.

The conflict in the DRC is the first interstate war in sub-Saharan Africa since Uganda invaded Tanzania in 1978, and only the third since 1960. Although Africa is seen as a hotbed of violence and warfare, most conflicts have been intrastate in nature. Norms of sovereignty reinforced by clauses in the charter of the Organization of African Unity (OAU) and the constitutions of the various subregional organizations have effectively prevented cross-border conflict from the time of independence until now. The Ugandan and Rwandan-led invasion of Congo, as well as the presence there of the Southern African Development Community (SADC) intervention force, therefore represents a watershed in the recent history of African conflict. It appears that the forces preventing cross-border conflict since 1960 have become seriously weakened.

What are the implications of the rise of interstate war in Africa for peace and security on the continent? Why have Western powers been so reluctant to take an active role in resolving Africa's first "world war"? And what impact will the changing nature of warfare in Africa have on U.S. policy and the role of the United Nations there?

Democratization in Africa examines the state of progress of democracy in Africa at the end of the 1990s. The past decade's "third wave" of democratization, the contributors argue, has been characterized by retreats as well as advances. In some cases, newly established democratic orders have devolved into pseudo-democracies while, in other cases, superficial changes have been used as a cosmetic screen for continuation of often brutal regimes. The volume makes clear, however, that political liberalization is making significant headway.

The first section of the book ("Assessing Africa's Third Wave") offers several broad analytical surveys of democratic change and electoral processes in the 48 sub-Saharan African states. Frequent abuses are noted, but several contributors find room for guarded optimism. The second section ("South Africa: An African Success?") focuses on the dramatic developments in South Africa, the most advanced democracy on the continent but one faced with enormous challenges in the aftermath of apartheid. Essays in this section examine such issues as the role of nongovernmental organizations in the new political order, the ongoing and linked problems of racial and economic division, the demographics of public opinion on democracy, and the viability of the country's new constitution. The third section of the book ("African Ambiguities") considers more closely several other African states-Ghana, Kenya, Uganda, the Gambia, and Nigeria-all at different crossroads in their progress toward democracy.

From the Introduction:

"For the past three decades, there has been no lack of reasons to be pessimistic about Africa's future. But a more balanced reading is called for . . . There is significantly greater political freedom and more space for civil society in Africa today than a decade ago. Even as some states have disintegrated, others are moving forward to reconstruction. There is also a new ideological and intellectual climate. Unlike during the false start of the first liberation that came with decolonization, Africa today evinces a new political sobriety that is hardened (and even jaundiced) by experience, but not without hope."