In addition, during training sessions, data were collected on imitation of vocal scripts and imitation of actions while viewing the video using a per opportunity measure to determine whether the simultaneous video modeling technique was being implemented as intended and determine if participants imitated during the priming condition even though this was not prompted or reinforced. During probe sessions and generalization sessions, frequency data were collected on scripted verbalizations, unscripted verbalizations, scripted play actions, and unscripted play actions. Operational definitions for all dependent variables are provided in Table 2.