Psilocybin and MDMA reduce costly punishment in the Ultimatum Game

Evolutionary Game Dynamics, Cooperation, and Costly Punishment

Is costly punishment altruistic? Exploring rejection of unfair offers in the Ultimatum Game in real-world altruists

In the Ultimatum Game (UG), incurring a cost to punish inequity is commonly termed altruistic punishment. This behaviour is thought to benefit others if the defector becomes more equitable in future interactions. However, clear connections between punishment in the UG and altruistic behaviours outside the laboratory are lacking. We tested the altruistic punishment hypothesis in a sample of extr...

The spatial ultimatum game.

In the ultimatum game, two players are asked to split a certain sum of money. The proposer has to make an offer. If the responder accepts the offer, the money will be shared accordingly. If the responder rejects the offer, both players receive nothing. The rational solution is for the proposer to offer the smallest possible share, and for the responder to accept it. Human players, in contrast, ...

For Members Only: Ingroup Punishment of Fairness Norm Violations in the Ultimatum Game

Although group membership has many privileges, members are expected to reciprocate those privileges. We tested whether in-group members would be punished more harshly than out-group members for marginal fairness norm violations within ultimatum game bargaining interactions. Participants considered monetary splits (of US$20) from in-group and out-group proposers, which ranged in proportion. Acce...

The Ultimatum Game Revisited

The starting point of this article is the result of one ultimatum game experiment one of many showing a huge deviation from the predictions of micro theory. However, further analysis gives an explanation of subject behavior that deserves to be seen as rational, if assumptions, such as a total secrecy resulting in no effects on reputation, are questioned. Respondersí actual behavior can be under...