Firms are more productive in larger cities. This paper investigates a potential explanation that was first proposed by Adam Smith: Larger cities facilitate greater division of labor within firms. Using a dataset of Brazilian firms, I first document that division of labor is indeed robustly correlated with city size, controlling for firm size. I propose a theoretical model in which this relation...

The evolutionary success of ants and other social insects is considered to be intrinsically linked to division of labor among workers. The role of the brains of individual ants in generating division of labor, however, is poorly understood, as is the degree to which interspecific variation in worker social phenotypes is underscored by functional neurobiological differentiation. Here we demonstr...

A major transition in evolution is the origin of a division between reproduction and work among individuals. Nowhere is this divide more striking than in social insects, where workers rarely produce offspring even though they are often capable of reproduction should the queen or king die. The molecular mechanisms that control worker reproduction remain largely unknown. We used a combination of ...