Proportion offered in the Dictator and Ultimatum Games decreases with amount and social distance.

Behavior in both the Dictator Game and the Ultimatum Game is of special interest because proposers often violate the predictions of normative economic theory: On average, offers in both games are higher than what would be considered income-maximizing. In the present study, the initial amount provided to the proposer and the social distance between the proposer and the respondent were both varied across a wide range, and the effects of these manipulations on offers in the Dictator Game and the Ultimatum Game were examined in a broad sample of participants recruited via MTurk. Although the amount offered was consistently higher in the Ultimatum Game, the proportion of the amount offered decreased as the size of the initial amount increased in both games. Moreover, the proportion offered also decreased as a function of the social distance between the proposer and the responder. The present results extend our knowledge of the determinants of proposers' behavior in two-person economic games and emphasize the importance of social distance and the amount of money at stake as factors that affect people's economic decisions.