The first play skills intervention (phase B) involved components commonly used to teach play skills to children with
autism (e.g., Barton & Wolery, 2010; Lang, Machalicek, et al., 2009). The participants’ teacher set out the appropriate toy set
during centers and used a least-to-most prompting hierarchy that involved gesture, model, verbal, and physical prompts to
directly teach play skills specific to the target toy set. Reinforcement in the form of social praise and small edibles (e.g.,
raisins) was delivered contingent upon occurrences of appropriate play behaviors. Initially, reinforcers were delivered on a
fixed ratio of one play behavior to one reinforcer (FR1). When appropriate play increased above baseline levels in two
consecutive sessions the teacher began to thin the reinforcement schedule until an average of three play behaviors were
required for every reinforcer (i.e., a variable ratio reinforcement schedule [VR3]). No programmed contingencies were in
place for stereotypy. However, if the child was engaged in stereotypy and did not respond to less intrusive prompts to play, a
physical prompt (i.e., gently guiding the participant’s hand) was delivered which, in effect, interrupted and redirected
stereotypy to appropriate play. Intervention in this phase continued until participants engaged in appropriate play during
60% of 10-s intervals or more for three consecutive sessions in which data were collected.