Lowes and Nunn test the theory that the transatlantic and Indian Ocean slave trades of the thirteenth to nineteenth centuries prompted a shift towards matrilineal kinship systems throughout sub-Saharan Africa. Controlling for ecological variables commonly thought to affect kinship structure (including ruggedness of terrain, suitability for agriculture, etc.), the authors find a significant correlation between the number of people enslaved from a given ethnic group, and the tendency of that group towards a matrilineal kinship system. Polygyny was also identified as a statistically significant characteristic of communities most impacted by the slave trade.

Through review of the economic literature and cross-cultural analysis of families (nuclear, stem, and complex), the authors show that family type is heterogeneous and argue that types other than nuclear have been largely ignored by economists. They encourage, based on their findings, further research on family structure and the development of better models for household decision making. They use ancestral populations in the ethnographic record to estimate country-level family patterns.

In this study, the author closely examines the educational outcomes of Christian missions in sub-Saharan African societies. He shows that there was local demand for formal education, but theorizes that this demand decreased in polygamous societies as Christian missionaries required monogamy for entry. His results show areas that experienced this struggle over polygamy are associated with worse educational outcomes than those that did not.

This paper examines the relationship of productive variation in land between ethnic groups to determine if an increased range of producible goods will increase trade, thus decreasing language diversity between neighboring groups. The author initially found that high-variation in land production lessened the diversity of language between ethnic groups in that area. To further test this correlation, the author found that high-productive variation increased trade and exogamous marriage and decreased inter-ethnic conflict. Based on these findings, the author suggests that neighboring ethnic languages co-evolved through the economic benefit of inter-ethnic trade and social interaction.

This paper adds to a body of research which analyzes the persistence of institutional features in societies over time by testing for association between local democracy (succession by consensus among preindustrial groups) and various measures of democracy in contemporary societies. The researchers conclude that beliefs and values which perceive democracy as a viable political structure may be an important mediating mechanism in producing and maintaining democratic instututions over time.