Stimulus class membership established via stimulus-reinforcer relations.
The reinforcer you pair with a stimulus can act as its class card; swap the consequence and the stimulus may jump to a new equivalence family without extra training.
01Research in Context
What this study did
The team taught two adults with intellectual disability a four-way match game. Each picture, spoken name, printed word, and food item shared the same consequence during training.
They used arbitrary matching-to-sample. If the learner picked the correct comparison, the linked food appeared. No extra praise or tokens were given.
What they found
Both adults soon treated all four items as one family. When the food partner changed, the picture quickly moved to the new family without further teaching.
The reinforcer itself acted like a class member. Swapping the edible rewired the whole network.
How this fits with other research
Dube et al. (1989) ran the same setup two years later and got the same result, showing the effect is reliable.
Fetterman et al. (1989) pushed further. They showed that only items with a reinforcement history entered the class; items that merely looked alike did not. This sharpens the 1987 claim: it is the consequence, not general similarity, that binds the class.
Plazas et al. (2018) used exclusion trials instead of food pairings and still built new classes. Together the papers widen our toolbox: both reinforcers and exclusion can create equivalence without direct training.
Why it matters
If you want flexible language or concept networks, watch what follows the stimulus. Change the edible, sticker, or praise partner and the node can slide to a new class. Test the shift with simple probe trials before reteaching everything. This saves hours of direct instruction and keeps the learner’s world coherent when natural contingencies change.
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02At a glance
03Original abstract
In an arbitrary matching-to-sample procedure, two mentally retarded subjects learned conditional discriminations with two sets of stimuli. Each set included a spoken name (N1 or N2), an object (O1 or O2), and a printed symbol (S1 or S2). One subject selected conditionally (a) O1 upon N1, and O2 upon N2, and (b) S1 upon O1, and S2 upon O2. The other subject selected conditionally (a) S1 upon N1, and S2 upon N2, and (b) O1 upon S1, and O2 upon S2. For both subjects, selections of O1 and S1 produced one type of food, F1; selections of O2 and S2 produced a different type of food, F2. Both subjects also learned identity-matching performances, selecting O1, O2, S1, S2, F1, and F2 conditionally upon those stimuli as samples; F1 followed selections of O1, S1, and F1; F2 followed selections of O2, S2, and F2. Matching performances consistent with stimulus class formation involving the names, objects, symbols, and foods were demonstrated on probe trials, even though these performances had not been taught explicitly. Next, new objects, X1 and X2, were presented on identity-matching trials, producing F1 and F2, respectively. Without further training, X1 was selected conditionally upon N1, S1, and O1, and X2 was selected upon N2, S2, and O2. When the contingencies were changed so that selections of X1 and X2 were now followed by F2 and F1, respectively, X2 was selected conditionally upon N1, S1, and O1, and X1 was selected upon N2, S2, and O2. Class membership of X1 and X2 had apparently changed. This study provides evidence that reinforcers may become members of stimulus classes, and that new stimuli may become class members through relations with reinforcers.
Journal of the experimental analysis of behavior, 1987 · doi:10.1901/jeab.1987.47-159