“…From Wahler's initial study, a large body of research has emerged on the power of peer reinforcement, either mediated by individuals or by groups (Furman, Rahe, & Hartup, 1979;Greenwood, Todd, Hops, & Walker, 1982;Odom, Hoyson, Jamieson, & Strain, 1985). Although the data are somewhat mixed, it is significant to note that when a direct comparison is made, peer-based group contingencies yield better outcomes than do adult-mediated approaches (Sancilio, 1987).…”