This study investigates how structured Mediated Learning Experiences may improve peer-cooperative communication within problem-solving task exercises. Two groups (n = 22) of Year 8 students (mean age 13 +/- 5 months) were randomly selected to participate in this study. The study began with two one-hour sessions of activity-based problem-solving tasks for the control and experimental groups. These sessions were coded for on and off-task communication. The experimental group then participated in a Mediated Learning Experience (MLE) focusing on building trust, effective communication and pro-social behaviour. Following the MLE, a one-hour problem-solving exercise for the collection of data related to on- and off-task communication was conducted for both the control and experimental groups. Results demonstrate that cooperative group on-task communication can be effectively influenced, both intra-group and inter-group, implying that the success associated with cooperative learning may be enhanced by first teaching students how to cooperate. (Contains 1 table.)