The effect of social motives, communication and group size on behaviour in an N-person multi-stage mixed-motive game

Two experiments investigated the impact of social motives or individuals' preferences for specific self–other outcome distributions, on behaviour in an n-person game. Subjects' social motives (altruistic, cooperative, individualistic, competitive) were assessed prior to the decision-making in either 7-person games (Experiment 1) or 20-person games (Experiment 2). A modification of the n-person game format normally employed is introduced in this research to permit the choices made by players on a given trial to modify the payoff matrix available to self and others on subsequent trials. The game format, a simulated social dilemma, was presented in terms of a conservation of resources problem. In Experiment 1 communication opportunities were manipulated. As predicted, there were consistent differences between the four classes of social motivation in the amount of the resources taken for self: competitive subjects took the most, individualistic subjects took less than the competitive ones but more than the average, while cooperative and altruistic subjects took the smallest amount of the resources for themselves. Moreover, competitive subjects expected the others to take fewer resources than they intended to themselves, and altruistic subjects expected the others to take more resources than they intended to themselves. These findings are only partly consistent with existing theories concerning the relationship between behaviour and expected behaviour of others. In addition, when communication was allowed, significantly fewer resources were taken for self. Contrary to the predictions based on previous research findings, subjects in the 20-person groups did not take more resources for self than subjects in the 7-person groups.