An experiment was conducted to evaluate the effects of the differential interchange of earning on preference for individual and social contingencies under conditions of symmetrical and asymmetrical inequality in the distribution of consequences in a situation of partial altruism. Four dyads of college students solved puzzles presented on a computer screen. In experimental phases, each subject in a dyad observed his or her peer's performance and put pieces in his or her puzzle as well as in the peer's puzzle. After baseline, the dyads were exposed in alternation to phases or interchange under conditions of equality and inequality of consequences. The first two phases of inequality were symmetrical, the other two phases were asymmetrical. At the end of the experiment, participants could exchange their earning for zero, one, or two CDs. The results confirm that in non-restrictive choice conditions, subjects prefer individual over social contingencies, even when doing so implies obtaining lesser gains. Results are discussed in terms of the manipulation of different variables, in addition to economic parameters, to promote social responses.