One of the important factors contributing to the current interest in the development of social competence in preschool children is the acceptance of such competencies as appropriate outcomes in the evaluation of preschool intervention programs. Measurement of social competence is still in an early stage of development. One problem is that behavioral descriptions are not easily applied to measurement of social competence. Another problem is that certain behaviors, such as pro-social behaviors, occur so rarely in the natural spontaneous events of the nursery school that measurement is almost impossible. Until recently there has been little research on basic cognitive processes involved in the development of social behavior in very young children. Lack of attention to young children was due to evidence which seemed to indicate that very little social development was possible until after the shift to cognitive operations which occurs when children are between 5 and 7 years of age. Recent work, however, suggests that major shifts in social competence do take place in the 3-5 year age period, and that this is a particularly fruitful time to focus new measurement approaches. (Author/SS)