Six experiments examined the effects of thank-you gifts on charitable giving. Results indicate that although people expect that the offer of thank-you gifts will increase donations, such offers actually reduce charitable donations. This effect was obtained across a wide variety of charities and...

Recent studies have identified the uncertainty effect (UE), whereby risky prospects (e.g., a binary lottery that offers either a $50 or $100 gift certificate) are valued less than their worst possible outcome (a $50 certificate). This effect has been proposed to result from ``direct...

Why do people purchase objects that were once owned by celebrities, such as film stars or politicians, and also by despised individuals, such as serial killers and notorious dictators? The present studies examine three potential explanations: mere associations, market demands, and contagion (the...

We study the experimental play of the repeated prisoner's dilemma when intended actions are implemented with noise. In treatments where cooperation is an equilibrium, subjects cooperate substantially more than in treatments without cooperative equilibria. In all settings there was considerable...

We explore the extent to which altruism, as measured by giving in a dictator game (DG), accounts for play in a noisy version of the repeated prisoner's dilemma. We find that DG giving is correlated with cooperation in the repeated game when no cooperative equilibria exist, but not when...

Trust is a central component of social and economic interactions among humans. While rational self-interest dictates that “investors” should not be trusting and “trustees” should not be trustworthy in one-shot anonymous interactions, behavioral experiments with the “trust game” have...

It is standard in experimental economics to use decontextualized designs where payoff structures are presented using neutral language. Here we show that cooperation in such a neutrally framed Prisoner’s Dilemma is equivalent to a PD framed as contributing to a cooperative endeavour....

Recent evidence suggests that individual variation in risk taking is partly due to genetic factors. We explore how self-reported risk taking in different domains correlates with variation in the dopamine receptor D4 gene (DRD4). Past studies conflict on the influence of DRD4 in relation to risk...

We explore the extent to which altruism, as measured by giving in a dictator game (DG), accounts for play in a noisy version of the repeated prisoner's dilemma. We find that DG giving is correlated with cooperation in the repeated game when no cooperative equilibria exist, but not when...