Equivalence classes generated by sequence training.
Sequence training builds ordinal equivalence classes, but showing items side-by-side and adding one meaningful picture now works better.
01Research in Context
What this study did
White et al. (1990) taught adults to tap colored squares in a set order. The team then tested if the learners treated new, untrained squares as belonging to the same "first, second, third" group.
No one told the adults the goal was to build equivalence classes. The study simply checked whether sequence practice alone could make people treat new items as part of the same ordinal family.
What they found
Most adults formed orderly classes. They correctly ranked new squares that had never appeared together during training.
When the team erased all hints, a few learners needed a quick review round. After that, the classes stayed solid.
How this fits with other research
Ayres‐Pereira et al. (2025) now tops this method. They got a large share success by showing look-alike items side-by-side instead of one at a time. The newer paper keeps the same goal—build equivalence—but swaps sequence training for simultaneous viewing.
Fields et al. (2012) and Weissman-Fogel et al. (2015) show a shortcut: drop one meaningful picture into the class. Success jumps from about a large share to a large share without any extra steps.
Guerrero et al. (2021) add a practical tip. Start with easy sound-plus-picture pairs, then fade to harder word-only tests. This keeps the class strong while White et al. (1990) relied on visual order alone.
Why it matters
You can still use sequence drills to teach ordinal concepts like days, months, or task steps. Just add two upgrades: show the items together at test and slip in one familiar picture. These tweaks, drawn from newer work, turn a shaky a large share success rate into near-perfect class formation.
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02At a glance
03Original abstract
In Experiment 1, 3, adult females were taught with verbal instructions and contingencies to select, in sequence, three arbitrary visual stimuli from an array of five stimuli. After four different sequences were taught, match-to-sample tests assessed emergent conditional relations among all stimuli that had been selected in the same order in the sequences. Subjects' performances indicated development of four stimulus classes, three based on ordinal position and one based on nonselection. Next, match-to-sample training established conditional relations between each of four novel figures and one member of each of the ordinal stimulus classes. Tests confirmed that the classes were equivalence classes, each expanded by one new member. In subsequent sequence tests, the new stimuli were selected in a sequence that was consistent with ordinal class membership. Experiment 2 replicated Experiment 1 with 2 different adult females, but the verbal instructions were omitted. Results were similar to Experiment 1, except that extensive review and retesting were required before expansion of the ordinal classes with the novel figures was observed.
Journal of the experimental analysis of behavior, 1990 · doi:10.1901/jeab.1990.53-47