The goal of the investigation was to eliminate the disruptive, resistant and assaultive behaviors and increase the appropriate peer interaction of an economically disadvantaged kindergarten white boy. The treatment program involved presentation of adult (teacher) attention contingent upon desirable classroom behavior, withholding of attention contingent upon inappropriate behavior, and social isolation contingent upon unacceptable behavior. The subject's behavior was classified according to the Coping Analysis Schedule for Educational Settings, and the teacher's interactions with the subject were categorized according to their content. Behavior and interactions were recorded by an observer. The program was carried out daily in the activities of free play, discussion, and rest. The subject's inappropriate and unacceptable behaviors significantly decreased when they were punished (isolation) rather than ignored. A reversal of the treatment program was introduced to demonstrate that the teacher's interactions were in fact the controlling variables. Reinstatement of data treatment had favorable results. The study indicates that the systematic use of social reinforcement techniques in the classroom can significantly change a child's behavior, even when the target is more comprehensive than the single operant. (Author/NH)