The effects of fixed ratio values on concurrent mand and play responses.

Three children diagnosed with pervasive developmental disabilities emitted a high rate of mands and a low-to-zero rate of appropriate play responses when the two responses were reinforced on concurrent Fixed Ratio 1 (FR1) schedules. When mands were reinforced on an FR10 schedule and play responses were concurrently reinforced on an FR1 schedule, play responses increased. Two participants' mands decreased from baseline levels but were maintained, and the third participant's mands increased. Implications of the use of choice procedures for clinical settings are discussed.