Children with disabilities often have deficits in imitation skills, particularly in imitating peers. Imitation is considered a behavioral cusp--which, once learned, allows a child to access additional and previously unavailable learning opportunities. In the current study, researchers examined the efficacy of contingent reinforcement delivered within a small group play context on the unprompted peer imitation (UPI) behaviors of three children with disabilities. UPI behaviors increased when contingent reinforcement was provided, and maintained with a thinned schedule of reinforcement. However, pretend play and social interactions did not increase concurrently with peer imitation. (author abstract)