Forging a New Identity: The Costs and Benefits of Diversity in Civil War Combat Units for Black Slaves and Freemen
研究了美国内战中黑人士兵（多为前奴隶）在多样化作战部队中的经历，发现短期通过减少偷懒和建立社会资本获益，但长期在异质部队中人力资本和信息获取更优。
By the end of the Civil War, 186,017 black men had fought for the Union Army and roughly threequarters of these men were former slaves. Because most of the black soldiers who served were illiterate farm workers, the war exposed them to a much broader world. The war experience of these men depended upon their peers, their commanding officers, and where their regiment toured. These factors affected the later life outcomes of black slaves and freemen. This paper documents both the short run costs and long run benefits of participating in a diverse environment. In the short run the combat unit benefited from company heterogeneity as this built social capital and minimized shirking, but in the long run men's human capital and aquisition of information was best served by fighting in heterogeneous companies.