Randell, T., & Remington, B. (1999).
Equivalence relations between visual stimuli: The functional role of naming.
Journal of the Experimental Analysis of Behavior,
71, 395-415.
The functionality of verbal behavior in equivalence class
formation was demonstrated by training 30 verbally able adults
using different combinations of the same easily nameable, yet
formally unrelated, pictorial stimuli. Match-to-sample baselines
for four four-member classes were established sequentially (i.e.,
AB-BC-CD), with participants in the rhyme condition trained to
select comparisons whose normative names rhymed with those of the
samples. For the orthogonal condition, class rearrangement was
such that on every trial all available comparisons' names rhymed
with each other, but not with the name of the sample. In the
diagonal condition, stimuli were allocated pseudorandomly as
samples and comparisons. Although all participants maintained
baseline discriminations prior to emergent testing, equivalence
was confined almost exclusively to the rhyme condition, in which
it was ubiquitous. These participants also required less training
than those in the control conditions, among whom effects of nodal
distance were observed most strongly. Subsequent testing
presented participants with no-reinforcement trials involving
novel pictorial stimuli, in which one of the available
comparisons' names always rhymed with that of the sample. All
rhyme participants consistently selected these comparisons.
Results indicate that visual stimuli are named, that the
phonological properties of those names can influence equivalence
class formation, and that the emergence of untrained
discriminations may, under certain circumstances, be rule
governed.
Key words: stimulus equivalence, naming, generalization, nodal
distance, match to sample, adult humans