The Child Development Project is a seven-year longitudinal study designed to promote prosocial behaviors (Battistich, Solomon, Watson, & Schaps, 1997; Battistich, Watson, Solomon, Schaps, & Solomon, 1991). The program provided opportunities for children to 1) engage in cooperative learning activities; 2) practice important social skills (i.e., understanding others' thoughts and feelings; and 3) provide help to others. Teachers were trained to provide the main components of the intervention. Subjects include 2438 fifth- and sixth-graders assigned to the treatment group and 2321 students assigned to the comparison group. Children in the program experienced increases in prosocial behavior and prosocial moral reasoning.