Stimulus equivalence and relational frame theory

Murray Sidman's view of stimulus equivalence as a basic stimulus function, and his preference for a largely procedural approach to the study of equivalence is outlined. Steven Hayes's relational frame account, which considers the equivalence relation as one of a number of derived stimulus functions, is also examined. The empirical implications arising from the main differences between these two accounts are discussed. Although relational frame theory does appear to readily predict at least one equivalence effect that Sidman's approach does not, it is still too early to decide which account is better. Reviewing the differences between these two accounts, however, should help to prevent conceptual and empirical confusion in future research