The Ash Twins Blog

Nelison et al (2009) find convincing evidence of costly fairness in a clever ultimate-game variant:

We investigated if responders accept a 50–50 split in a modified version of the ultimatum game, in which rejection yields a higher payoff (€7) than accepting the equal offer (€5). Therefore, the decision to accept the 50–50 split in this modified ultimatum game cannot be perceived as a self-interest act, as opposed to the standard game, in which acceptance may reflect resignation in the knowledge that the equal split is the best one can expect. A substantial proportion [55%] of responders accepts the equal split in this modified game (Study 1), which clearly establishes egalitarian preferences. Further studies show that the willingness to accept is not an artifact of indifference towards the extra payoff (Study 2), but reflects true concerns for proposers’ outcomes (Study 3).