Wirth, O., & Chase, P. N. (2002).
Stability of functional equivalence and stimulus equivalence:
Effects of baseline reversals.
Journal of the Experimental Analysis of Behavior,
77, 29-47.
Functional equivalence and stimulus equivalence classes were
established, reversed, and tested for stability with college
students. Functional stimulus classes were established using a
task in which students were trained to say nonsense words in the
presence of arbitrarily assigned sets of symbols.
Computer-controlled speech-recognition technology was used to
record and analyze students’ vocal responses for accuracy. After
the establishment of stimulus classes was demonstrated with a
transfer-of-function test, the effects of reversing selected
baseline simple discriminations were assessed during an
additional transfer-of-function test and a follow-up test that
occurred several weeks later. With the same students, stimulus
equivalence classes were established and demonstrated with
computerized matching-to-sample procedures. The effects of
reversing selected baseline conditional discriminations also were
assessed during a postreversal equivalence test and a follow-up
test. Both functional stimulus classes and stimulus equivalence
were sensitive to contingency reversals, but the reversals with
stimulus equivalence classes affected stimulus class organization
whereas reversals with functional stimulus classes did not.
Follow-up performances were largely consistent with the original
baseline contingencies. The similarities and differences between
stimulus equivalence and functional equivalence are related to
the specific contingencies that select responding in the presence
of the stimuli that form the classes.
Key words: stimulus classes, functional equivalence, stimulus
equivalence, speech recognition, matching to sample, naming,
vocal behavior, humans