Summary
The Premack principle and special instructional exercises were used in an attempt to increase fourth graders' problem solving skills. From 12 classrooms 240 children from different ethnic and socioeconomic backgrounds were assigned to either a training-plus-reward, a training-only, or a control condition. In return for daily work on problem solving worksheets during a nine-week training period, the reward group was given free-time periods and numerous games, books, and art supplies. The training-only group made use of the worksheets as part of the regular classwork. At the end of the program, problem solving performance in both training groups had increased over controls, but the training-only group performed at the highest levels. Socioeconomic differences were also observed.