For almost two decades, Virginia has used risk assessment to justify “alternative” nonprison sentences for eligible drug and property offenders. In Study 1, we examined how frequently alternative sentences actually were imposed. We found that alternative sentences were given to only 42% of...

We examine the effect of payoff variations on cooperation in one-shot prisoner's dilemma games. We focus on three factors: risk, temptation, and efficiency, which we vary as orthogonal treatments. We find that temptation has the largest impact on cooperation. Temptation directly deters...

We study environments in which agents are randomly matched to play a Prisoner's Dilemma, and each player observes a few of the partner's past actions against previous opponents. We depart from the existing related literature by allowing a small fraction of the population to be commitment types....

Existing research supports two opposing mechanisms through which positive mood might affect cooperation. Some studies have suggested that positive mood produces more altruistic, open and helpful behavior, fostering cooperation. However, there is contrasting research supporting the idea that...