In the midst of global recession, angry citizens and media pundits often offer simplistic theories about how bad decisions lead to crises. Many economists, however, base their analyses on rational choice theory, which assumes that decisions are made by well-informed, intelligent people who weigh risks, costs, and benefits. Taking a more realistic approach, the field of anthropology carefully looks at the underlying causes of choices at different times and places.

Using case studies of choices by farmers, artisans, and bureaucrats drawn from Michael Chibnik's research in Mexico, Peru,...