We study the evolution of both characteristics of reciprocity: the willingness to reward and the willingness to punish. First, both preferences for rewarding and preferences for punishing can survive provided that individuals interact within separate groups. Second, rewarders survive only in...

This paper shows how the fear of signaling distrust can endogenously lead to incomplete contractual agreements. We consider a principal agent relationship where the agent may be trustworthy (dedicated to the project) or not. The principal may trust the agent (i.e. have a high belief of facing a...

The separation of the legislative, executive, and judiciary powers is a key principle in most democratic constitutions. We analyze the costs and benefits of separating legislature and executive in an incomplete contracts model: the executive can decide to implement public projects. Under...

We provide necessary and sufficient conditions on an individual's expected utility function under which any zero-mean idiosyncratic risk increases cautiousness (the derivative of the reciprocal of the absolute risk aversion), which is the key determinant for this individual's demand for options...

In an exchange economy in which there is a complete set of markets for macroeconomic risks but no market for idiosyncratic risks, we consider how the efficient risk-sharing rules for the macroeconomic risk are affected by the heterogeneity in the consumers' risk attitudes and idiosyncratic...

How should we make value judgments about wealth inequality? Harsanyi (1953) proposes to take an individual who evaluates her well-being by expected utility and ask her to evaluate the wealth possibilities ex-ante (i.e. before she finds her place in society, i.e., under the "veil of ignorance" of...