A study was conducted to examine the applicability of social comparison and social exchange theories to the family unit. One part of that study concentrated on the effect of the belief that one's parents favored or did not facor oneself over the sibling. College students (N=216) from two-child families were asked to indicate their perception of whether or not the parents favored one sibling over the other. Subjects provided information about the relationships in the two-child family, including closeness and the amount of goods, services, and esteem the parents presently give to each sibling. In addition, subjects indicated feelings of debt and obligation toward the parents and completed three personality scales. The results indicated that respondents who believed they were favored were more likely to be first-born. Favored subjects indicated a belief that they were closer to the parents than was the sibling in both absolute and relative terms. Those believing themselves to be favored were more likely to state a greater sense of obligation to the parents and to act in a way that would please the parents. They also indicated a greater likelihood of actively helping the parents in the future. These findings follow social exchange principles that the recipient of excess rewards incurs an obligation of reciprocity than can be expressed in both emotional and tangible forms. (NB)