The present study evaluated the effects of a lag differential reinforcement contingency on 2 students' activity selections using reversal designs. Results showed that the lag contingency was responsible for promoting increased novel selections, engagement in diverse activities, and greater progress with respect to programmed academic activities.

Recently, nonmaternal center-based child care has been linked to problem behavior in young children (National Institute of Child Health and Human Development, 2003). In response, a comprehensive program to promote prosocial skills was evaluated in a classroom of 16 children between the ages of 3 years and 5 years. Classroom observations were…