The author develops a model of informal role relations in small, closed groups, i.e., two- or three-person relations. There are four types of interaction: one-sided behavior or mutual behavior, each with either 'symmetric' (identificatory) or 'complementary' positions of the participants. It appears that symmetrical mutualities develop in an escalating manner, while the other types tend to remain stable over time. Complementary mutualities have special significance in that they occur under repressive pressure. Only in such circumstances do they provide satisfaction and protect the internal stability of small groups. The sanctioning mechanisms which stabilize roles are discussed and illustrated by reference to the doctor-patient relationship.