This paper examines the reflexive interplay between individual decisions and social forces to analyze the evolution of cooperation in the presence of "multi-directedness," whereby people's preferences depend on their psychological motives. People have access to multiple, discrete motives....

This paper examines how skill-biased growth can generate economic fragmentation (income dis-parities) that give rise to social fragmentation (the adoption of increasingly incompatible social identities and values), which generate political fragmentation (the adoption of increasingly incompatible...

This paper models the welfare consequences of social fragmentation arising from technological advance. We start from the premise that technological progress falls primarily on market-traded commodities rather than prosocial relationships, since the latter intrinsically require the expenditure of...