The application of behavior modification procedures by Head Start teachers in the classroom and the remedial application of programmed instructions to children with preacademic deficiencies were studied in 11 classrooms located in three Kansas towns--Lawrence, Topeka, and Kansas City. Data were collected throughout the 1968-1969 year on both the children and the head teacher. All children were pre- and post-tested on the Social Interaction Observation measure. One observer was assigned to each class. Four classes served as controls; one class received the remedial application of programed instruction; two classes had behavior modification procedures applied; and four classes were given both procedures. Seven children with special behavior problems were chosen by teachers in the behavior modification classes for study. Meetings were held once a week among the teacher, observers, and the Intervention Coordinator to discuss the progress of the child. Each individual study is described in detail, with six being successful in outcome. It is concluded that behavior modification can be effectively applied in Head Start classrooms. Teachers were able to increase verbal behavior, peer interaction, and duration in activities by applying the simple procedures of "priming" and "social reinforcement." Teachers were trained to use behavior modification principles effectively. Tables and figures provide the statistical data and samples of forms used. (DB)