Naming in conditional discrimination and stimulus equivalence.
Check that emergent matching is not just a repeated response habit.
01Research in Context
What this study did
The author looked back at earlier monkey studies that claimed to show stimulus equivalence.
He asked: did the animals really link stimuli, or did they just keep pressing the same keys?
The paper warns that matching-to-sample results can fool you if you ignore response patterns.
What they found
The monkey "equivalence" could be explained by preserved response patterns, not mental links.
In other words, the monkeys kept doing what had worked before, not understanding relations.
The study says we must add extra checks before claiming true stimulus equivalence.
How this fits with other research
McIntire et al. (1987) first reported monkey equivalence; Marr (1989) now says that claim was too bold.
Bromley et al. (1998) later added more controls for parakeets, building on the same worry.
Vollmer et al. (1996) still backs naming-based equivalence in kids, showing the issue is mostly with non-human tests.
Why it matters
Before you say a client "has equivalence," test with new responses and mixed trial orders.
If you only use one key or one gesture, you may be shaping a habit, not a relation.
Add probe trials with swapped responses to be sure the links are real.
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02At a glance
03Original abstract
Using a matching-to-sample procedure, McIntire, Cleary, and Thompson (1987) taught monkeys the conditional relations A1-R1-A1-R1, A2-R2-A2-R2, A1-R1-B1-R1, A2-R2-B2-R2, B1-R1-C1-R1, and B2-R2-C2-R2, where the first and third terms in each relation refer to the sample and comparison stimuli, respectively, and the second and last terms refer to the emission of a distinctive pattern of responding. The subjects were then tested for the emergent relations A-C, C-A, B-A, C-B, and B-B, with the differential response produced by a given stimulus during training also emitted on test trials (e.g., A1-R1-C1-R1). The performances of both subjects were as accurate on the tested relations as they had been on the trained relations. The new relations were characterized as demonstrations of stimulus equivalence. However, the conditional discrimination literature shows that such training procedures generate control of comparison selection by the differential response patterns. Therefore, no emergent relations were demonstrated because all of the trained response-stimulus relations were preserved on test trials. This paper suggests that these procedures do not provide an appropriate analogy for the kind of emergent stimulus-stimulus relations exhibited by human subjects in equivalence studies and outlines a paradigm for assessing the relative influence of stimulus-stimulus and response-stimulus relations.
Journal of the experimental analysis of behavior, 1989 · doi:10.1901/jeab.1989.51-379