This paper studies how the swiftness and delay of punishment affect behavior. Using rich administrative data from automated speed cameras, we exploit two (quasi-)experimental sources of variation in the time between a speeding offense and the sending of a ticket. At the launch of the speed...

Communal responsibility, a medieval institution studied by Greif (2006), supported the use of credit among European merchants in the absence of modern enforcement technologies. This paper shows how this mechanism helps to overcome enforcement problems in anonymous buyer/seller transactions. In a...