Natural Experiments of History (review)

In recent years, historical studies have veered sharply away from quantification and economics. Economic historians are a rare breed in American history departments, and most historians shy away from numbers. This collection of essays, edited by two well-known non-historians whose work has evinced a strong interest in history, makes a strong case that historians should not abandon their training in the social sciences in favor of the now seemingly dominant trend of narrative history.

The book’s title, Natural Experiments in History, is likely to be unfamiliar to most historians. What the editors and contributing authors intend by these words is a form of comparative history. More often than many realize, history offers opportunities to compare “different systems that are similar in many respects but that differ with respect to the factors whose influence one wishes to study” (2). Moreover, in their opinion, comparative history can provide answers to crucial historical questions that many historians have concluded are likely to prove unanswerable given available methods and source materials. These essays tackle such compelling issues as why some countries grow rich and others do not; whether the slave trade from Africa raised insuperable barriers to the economic progress of the continent; and why Haiti, once the richest colony in the Caribbean, is now the poorest country in the Americas while its next-door neighbor, the Dominican Republic has been spared much of this deep poverty. Although some of the essays fall short of the mark and will comfort those historians inclined to view their discipline as a humanistic enterprise rather than a branch of the social sciences, three of the chapters succeed admirably.

Among the chapters likely to be of most interest to historians, the best is the essay by Diamond, well known for Gods, Germs, and Steel: The Fates of Human Societies (New York, 2005), his Pulitzer Prize winning book. Here, Diamond assumes the fascinating challenge of why two countries sharing the same island, which the Spanish called Hispaniola—Haiti (originally Saint Domingue) and the Dominican Republic—have experienced such different histories. Inviting his readers to accompany him on an airplane flight above the island, he identifies the border between the two countries and notes the stark differences between them. Haiti, the poorer country, is an ecological ruin, deeply deforested and lacking abundant roads and rich agricultural estates. In glaring contrast, its neighbor has rich forestation, many roads, lush agricultural estates, obvious signs of a productive agricultural economy, and an average per capita income six times that of Haiti.

What explains the enormous present-day differences of these two countries? Those who know Diamond’s early work will not be surprised that location and climate play a major role in his explanation. The eastern side of the island—the Dominican Republic—receives more rainfall than Haiti and, as a consequence, was not endangered as severely with deforestation. But this is only part of the story. Far more influential were the different eighteenth-century colonial experiences. Haiti became France’s lucrative sugar colony, one of the wealthiest areas in the entire Caribbean. The French imported massive numbers of African slaves to the colony, half a million by the end of the eighteenth century, thereby creating subsequent problems with population density and accelerating deforestation. In contrast, the colony of Santo Domingo was unimportant to the Spanish. More interested in extracting precious metals from Peru and Mexico, the Spanish colonial officials neglected the Caribbean.

In the twentieth century, both countries had nasty dictators. But the Dominican Republic’s ruler, Rafael Trujillo, encouraged plantation and export agriculture, mainly for his own enrichment, whereas François Duvalier, his Haitian counterpart, worried only about his political base at the expense of the country’s economy. The result was Haitian impoverishment and Dominican development—a superb example of the comparative method in action.

Less successful but stimulating and provocative nonetheless is the quantitative essay by Nathan Nunn, who sets himself the task of investigating the causes and consequences of Africa’s slave...