Optimizing equivalence-based instruction: Effects of training protocols on equivalence class formation.

The team compared two ways to teach college students new equivalence classes. One group got simple-to-complex training: easy matches first, then probes mixed in. The other group got all matches at once, then a big test block.

They used an alternating-treatments design so each learner tried both methods. The goal was to see which path built three- and four-member classes faster.

Simple-to-complex won. Every adult formed classes right away with that method. The simultaneous block method worked for only three out of four people on three-member sets and fewer than half on four-member sets.

In plain words, sprinkling quick checks between easy steps beats cramming everything and hoping it sticks.

Frampton et al. (2023) extends the win: when learners also drew graphic organizers during simple-to-complex training, scores jumped from 75% to 100%. The same basic sequence, just with a note-taking boost.

Williams et al. (2025) conceptually replicates the pattern. Their rule-plus-examples sequence (another step-by-step approach) beat massed practice every time, showing the wider rule: feed material in small, ordered bites.

Whitehouse et al. (2014) seems to clash at first glance. That study found massed trials beat spaced trials for teaching tacts to kids with autism. The difference is content and probes. Whitehouse et al. (2014) massed tact repetitions with no early tests; the target paper interspersed probes during simple-to-complex training. Early checks, not just massing, appear key for equivalence.

If you run matching-to-sample lessons for staff training or client academics, swap from big test blocks to a simple-to-complex flow. Start with easy relations, drop in quick probe trials, then grow the set. You will likely see mastery sooner and cut re-teach time. Try it next session: teach two new stimuli, probe once, add the third, probe again—keep the cycle tight.