Social decisions under risk. Evidence from the probabilistic dictator game

This paper reports results of a 'probabilistic dictator game' experiment in which subjects had to allocate chances to win a prize between themselves and a dummy player. We have manipulated (within subjects) two aspects of the game: the relative values of the prizes (being equal for the two players, higher for the dictator or higher for the dummy) and the nature of the lottery determining the earnings: we used independent draws for the two players ('noncompetitive' condition) or a single draw ('competitive' condition). We have also asked for decisions in a standard, non-probabilistic, setting. Main results can be summarized as follows: First, a substantial fraction of subjects do share chances to win, also in the competitive treatments, thus showing concern for the other player that cannot be explained by outcome-based inequality aversion or quasi-maximin models. Second, this concern hardly ever leads to equalizing expected payoffs. Third, subjects appear to be somewhat efficiency-oriented, as they share more when partner's prize is relatively high. Keywords: social preference