The assumption that preferences are transitive, or, equivalently, that choice behavior satisfies the Weak Axiom of Revealed Preference, is at the core of most economic theory. While this is a natural assumption, one could ask the degree to which it is restrictive: are there objectives that could...

Suppose an altruistic person, A, is willing to transfer resources to a second person, B, if B comes upon hard times. If B anticipates that A will act in this manner, B will save too little from both agents' point of view. This is the Samaritan's dilemma. The logic of the dilemma has been...

A preference for negative reciprocity is an important part of the human emotional repertoire. We model its role in sustaining cooperative behavior but highlight an intrinsic free-rider problem: the fitness benefits of negative reciprocity are dispersed throughout the entire group, but the...

Donors who try to impose policy conditionality on countries receiving their aid commonly face conflicting incentives between using aid to induce income-increasing reforms and using aid to assist low-income countries: this conflict can lead to a time-consistency problem.This paper offers a...