THE SEARCH FOR STIMULUS EQUIVALENCE IN NONVERBAL ORGANISMS

A currently unresolved issue in stimulus equivalence research is the r elation of equivalence and language competence. The current consensus is that equivalence according to widely adopted criteria proposed by S idman has not yet been demonstrated in nonverbal experimental subjects . This judgment rests primarily on the failure of nonhuman subjects to display the equivalence outcome under conditions comparable to those used with human subjects. We discuss theoretical and methodological is sues that arise in research seeking to delineate the ''lower limits'' of equivalence phenomena in studies with laboratory animals or nonverb al humans. We propose a behavior-analytic approach to the question, ex amine the relationship between functional stimulus classes and equival ence classes, and describe some preliminary studies.