This paper describes an on-going study in which clinical research techniques are used to examine children's social cognition and its development. The study focuses on the relation between subjects' verbally expressed reasoning about social issues in two situations: during interview sessions and in natural life settings. Subjects for the study are 7- and 15-year-old children enrolled in an educational and psychological treatment program for learning and emotionally disabled children. One aspect of the research involves the identification and structuring of situations in which interpersonal reasoning can be studied. Another aspect involves the development of charts which identify developmental stages in reasoning about specific interpersonal issues. Final analyses are expected to provide data on developmental aspects of interpersonal reasoning, on longitudinal stability or changes in the reasoning of individuals and groups, on situational and personality factors which influence reasoning levels, and on the differences in reasoning levels during interview sessions as opposed to real life situations. Examples of preliminary findings in these areas are reported. Tables are included which present definitions of the interpersonal issues studied (e.g., self-reflection, jealousy, decision-making) and outline the sequence of stages identified for interpersonal and impersonal (Piagetian physical-cognitive) devlopment. (BD)