This paper presents a formal theory of reciprocity. Reciprocity means that people reward kind actions and punish unkind ones. The theory takes into account that people evaluate the kindness of an action not only by its consequences but also by the intention underlying this action. The theory...

Economists draw important lessons for modern development from the medieval Maghribi traders who, according to Greif, enforced contracts multilaterally through a closed, private-order ‘coalition’. We show that this view is untenable. The Maghribis used formal legal mechanisms and entered...

We analyze the relationship between legal institutions, innovation and growth. We compare a rigid (law set ex-ante) legal system and a flexible one (law set after observing current technology). The flexible system dominates in terms of welfare, amount of innovation and output growth at...

The medieval Champagne fairs are widely used to draw lessons about the institutional basis for long-distance impersonal exchange. This paper re-examines the causes of the outstanding success of the Champagne fairs in mediating international trade, the timing and causes of the fairs’ decline,...

Using data from the German Socio-Economic Panel from 1984-2009, we follow persons from their working life into their retirement years and find that, on average, employed people maintain their life satisfaction upon retirement, while long-term unemployed people report a substantial increase in...

In public good games, voluntary contributions tend to start off high and decline as the game is repeated. If high contributors are matched, however, contributions tend to stay high. We propose a formalization predicting that high contributors will self-select into groups committed to charitable...

We consider rules (strategies, commitments, contracts, or computer programs) that make behavior contingent on an opponent’s rule. The set of perfectly observable rules is not well defined. Previous contributions avoid this problem by restricting the rules deemed admissible. We instead limit...

According to the Framework Convention on Climate Change, global collective action is needed to stabilize “greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous [our emphasis] anthropogenic interference with the climate system.” The Framework Convention thus...