Saunders, R. R., & Green, G. (1999).
A discrimination analysis of training-structure effects on stimulus equivalence outcomes.
Journal of the Experimental Analysis of Behavior,
72, 117-137.
Experiments designed to establish stimulus equivalence classes
frequently produce differential outcomes that may be attributable
to training structure, defined as the order and arrangement of
baseline conditional discrimination training trials. Several
possible explanations for these differences have been suggested.
Here we develop a hypothesis based on an analysis of the simple
simultaneous and successive discriminations embedded in
conditional discrimination training and testing within each of
the training structures that are typically used in stimulus
equivalence experiments. Our analysis shows that only the
comparison-as-node (many-to-one) structure presents all the
simple discriminations in training that are subsequently required
for consistently positive outcomes on all tests for the
properties of equivalence. The sample-as-node (one-to-many)
training structure does not present all the simple
discriminations required for positive outcomes on either the
symmetry or combined transitivity and symmetry (equivalence)
tests. The linear-series training structure presents all the
simple discriminations required for consistently positive
outcomes on tests for symmetry, but not for symmetry and
transitivity combined (equivalence) or transitivity alone.
Further, the difference in the number of simple discriminations
presented in comparison-as-node training versus the other
training structures is larger when the intended class size is
greater than three or the number of classes is larger than two.
We discuss the relevance of this analysis to interpretations of
stimulus equivalence research, as well as some methodological and
theoretical implications.
Key words: stimulus equivalence, stimulus classes, simple
discrimination, conditional discrimination, discrimination
learning, stimulus relations