The present study sought to evaluate a sequence of training procedures on the emergence of foundational relational responses that underly more complex distinctive (i.e., difference) and hierarchical (i.e., categorical) relational frames. In a multiple baseline design, an initial baseline period with three children with Autism showed that the participants did not select nonidentical stimuli from an array when presented the contextual cue "different." Simple discrimination training was efficacious in establishing this response and the skill transferred to a novel set of stimuli without reinforcement. In a second baseline period, participants did not demonstrate conditional identical/nonidentical relational responses when provided the contextual cues "same" and "different." Conditional discrimination training with all three participants was again efficacious in establishing the conditional reflexive and distinctive responses and the skill transferred to untrained stimuli. In a third baseline period, participants did not demonstrate correct conditional categorization/sorting. Like in the prior two training conditions, training was efficacious in establishing the target response with a generalized transfer to untrained stimuli.
