Effects of multiple versus chained schedules on stereotypy and item engagement.

We evaluated rates of automatically reinforced stereotypy and item engagement for 2 children with autism under multiple and chained schedules in a multielement design. Each schedule included components during which stereotypy was blocked (S-) or allowed (S+), and we used colored cards as schedule-correlated stimuli. We report rates of stereotypy and item engagement during S- and S+ components, as well as the percentage of component time that elapsed before the first instances of stereotypy and item engagement. We observed less stereotypy and more consistent item engagement during chained-schedule sessions, and stimulus control of stereotypy and item engagement was established with the chained schedule. A subsequent concurrent-chains analysis revealed participant preference for the chained schedule. These results highlight the importance of contingent access to stereotypy when therapists attempt to gain stimulus control of stereotypy and increase functional item engagement.