We consider the possibility that cooperation in a prisoner's dilemma is fostered by people's voluntarily enhancement of their own vulnerability. The vulnerability of a player determines the effectiveness of possible punishment by the other. In the Gradual mechanism, players may condition their...

Choice shifts occur when individuals advocate a risky (safe) decision when acting as part of a group even though they prefer a safe (risky) decision when acting as individuals. Even though research in psychology and economics has produced a mass of evidence on this puzzling phenomenon, there is...

Social norms permeate society across a wide range of issues and are important to understanding how societies function. In this paper we concentrate on 'bad' social norms - those that are inefficient or even damaging to a group. This paper explains how bad social norms evolve and persist; our...

We consider the possibility that cooperation in a prisoner's dilemma is fostered by people's voluntarily enhancement of their own vulnerability. The vulnerability of a player determines the effectiveness of possible punishment by the other. In the 'Gradual' mechanism, players may condition their...