Participants in laboratory games are often willing to alter others' incomes at a cost to themselves and this behaviour has the effect of promoting cooperation. What motivates this action is unclear: punishment and reward aimed at promoting cooperation cannot be distinguished from attempts to...

Scholars have recently extended the traditional calculus of participation model by adding a term for benefits to others. We advance this work by distinguishing theoretically a concern for others in general (altruism) from a concern for others in certain groups (social identification). We posit...

The Southern California Twin Register was initiated in 1984 at the University of Southern California, and continues to grow. This paper provides an update of the register since it was described in the 2002 special issue of this journal. The register has expanded considerably in the past four...

Rational partisan theory's exclusive focus on electoral uncertainty ignores the importance of policy uncertainty for the economy. I develop a theory of policy risk to account for this uncertainty. Using an innovative measure of electoral probabilities based on Iowa Electronic Markets futures...

A recent model by Panchanathan and Boyd suggests that mutual aid among cooperators can promote large-scale human cooperation without succumbing to a second order free riding problem in which individuals receive aid without giving it. In a companion article, Fehr claims the model "solves [the]...

How did human cooperation evolve? Recent evidence shows that many people are willing to engage in altruistic punishment, voluntarily paying a cost to punish noncooperators. While this behaviour helps to explain how cooperation can persist, it creates an important puzzle. If altruistic punishment...

Altruistic punishment is a behaviour in which individuals punish others at a cost to themselves in order to provide a public good. Fehr and Gächter1 present experimental evidence suggesting that negative emotions toward non-cooperators motivate punishment which, in turn, facilitates high levels...

We develop an agent-based model of dynamic parties with social turnout built upon developments in different fields within social science. This model yields significant turnout, divergent platforms, and numerous results consistent with the rational calculus of voting model and the empirical...