Establishing auditory stimulus control over an eight-member equivalence class via conditional discrimination procedures.
After conditional-discrimination training, a single spoken word can control responding to every item in an eight-member picture class.
01Research in Context
What this study did
The team taught four adults to match eight different sounds to eight different shapes.
Each sound became the “name” for one shape. The learners never saw all eight pairs at once.
Instead they got trial-by-trial conditional-discrimination training: hear the sound, pick the correct shape, get feedback.
What they found
After training, every person treated the whole set like a single class.
When they heard any sound, they could point to every other shape in that class without extra teaching.
Three people showed this right away; one needed a short booster. The classes stayed intact months later.
How this fits with other research
Cordova et al. (1993) repeated the idea with smaller, three-to-four-member sound classes and got the same result.
Ayres‐Pereira et al. (2025) pushed the method further. They showed that when shapes look almost identical, you must present them side-by-side during training or classes fall apart.
Fields et al. (2021) added a timing twist: separate the response window from the comparison screen and class formation doubles. Together these papers show the 1988 recipe still works, but small tweaks make it stronger.
Why it matters
You can link a spoken word to a whole set of pictures in one shot. This is how we teach categories like “fruit,” “vehicle,” or “emotion” to learners with autism. Run conditional-discrimination trials with the label as the sample and the pictures as comparisons. Once the class forms, the label will evoke any picture and vice versa—no extra drills needed.
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02At a glance
03Original abstract
Two eight-member equivalence classes of visual stimuli were established during three phases of a training program. In Phase 1, two training arrangements were compared. In one, 3 subjects were taught on different trials to select from a single pair of comparison stimuli (A1, A2) in response to eight sample stimuli that were trained in pairs (B1, B2; C1, C2; D1, D2; E1, E2). In the second arrangement, subjects were taught to select from four pairs of comparisons (B1, B2; C1, C2; D3, D2; E2, E2) in response to two samples (A1, A2). Training with the single pair of comparison stimuli resulted in the development of equivalence relations (B1C1, B2C2, D1B1, D2B2, B1E1, B2E2, C1D1, C2D2, C1E1, C2E2, D1E1, D2E2, and their reciprocals) between the sample stimuli without direct training of these relations. In the other training arrangement, these relations among the comparison stimuli developed in the performance of 1 subject only. In Phase 2, three new pairs of stimuli (F1, F2; G1, G2; H1, H2) were substituted for three of the original pairs (B1, B2; C1, C2; D1, D2) and the training arrangements for the groups were reversed. Following training, the performances that showed equivalence relations on the probes in the first phase also showed equivalence relations in the second phase. If such relations did not develop in the first phase, they did not do so in the second phase. In Phase 3, relations between stimuli across the two previous phases (e.g., B1F1, B2F2, B1G1, B2H2, C1F1, etc.) were investigated. The 4 subjects whose performances showed the development of these relations were taught to select one stimulus from each class (E1 and E2) in response to a verbal label (I1 and I2) and then were tested to see if the verbal label controlled responding to the remaining members of the class (e.g., I1A1, I2A2, I1B1, I2B2, etc.). For 3 subjects, this generalized control occurred; for the 4th, generalization occurred only after verbal training with a second pair of visual stimuli (F1 and F2). In retests several months later, these auditory-visual relations were found to be intact or, if not, were recovered without direct training.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.49-95