Cooperation among strangers with and without a monetary system

Human societies prosper when their members move beyond local exchange and cooperate with outsiders in the creation of wealth. Collaboration of this type presents formidable challenges because interaction is impersonal, reciprocity is unfeasible and trust cannot be easily established. Here we study this cooperation problem by modeling strategic interaction among strangers through an Intertemporal Exchange Game. The setup can be easily implemented in the laboratory to study a variety of cooperation-enhancing institutions. In particular, we study the role of a fiat monetary system by introducing intrinsically worthless tokens that can be offered in exchange for cooperation. The experiments show that a monetary system spontaneously emerges in the laboratory, and is a key institution to promote cooperation among strangers.