In an experiment, the effects of types of outcomes on social value orientations (individualism, competition, pro-social orientation) were investigated. Ninety-nine students made 28 choices which affected outcomes (points to be converted into money) for themselves and another (unknown) person. About half of them started out with nothing but they could allocate positive outcomes (gains) to themselves and/or the other. The other half were told that they themselves and another person would start out with some outcomes but they could lose outcomes depending on the choices. For about half the participants it was certain that their choices would result in outcomes while for the other half outcomes would be likely rather than certain. The expected utility of the outcomes was the same in the four conditions. In accordance with prospect theory, it was expected and found that participants would be more individualistic in the conditions with losses than in the conditions with gains. In accordance with social comparison theory, it was expected and found that participants would be more competitive in the conditions with probable outcomes than in the conditions with certain outcomes. Copyright © 2002 John Wiley & Sons, Ltd.