A Comparison of Match-to-sample and Respondent-type Training of Equivalence Classes

Throughout the 25-year history of research on stimulus equivalence, one feature of the training procedure has remained constant, namely, the requirement of operant responding during the training procedures. The present investigation compared the traditional match-to-sample (MTS) training with a more recent respondent-type (ReT) procedure. Another consistent feature of the equivalence paradigm is the apparent stipulation that both training and testing must occur before equivalence emerges. In this respect, a more idiosyncratic measure of class acquisition would be desirable. Multidimensional scaling, as a class of exploratory techniques, is introduced as a possible addition to the stimulus equivalence paradigm. Results from 35 subjects in 3 experiments suggest that while the respondent-type training method can be an effective procedure, the operant-based match-to-sample method was clearly more effective in tests for symmetry, equivalence, and extended equivalence. The addition of a scaling procedure proved valuable and showed that both training methods facilitated the emergence of derived relations to varying degrees. Results are evaluated in relation to the importance of broadening the necessary and sufficient training conditions and response requirements for the emergence of stimulus equivalence.