Effects of preliminary class membership on subsequent stimulus equivalence class formation
Use familiar pictures as class hubs; old teaching materials drag success down.
01Research in Context
What this study did
Adults with no learning disability joined a lab experiment.
Each person was randomly placed in one of three groups.
Group one started with picture cards they already knew.
Group two started with cards that had been used in earlier lessons.
Group three got fresh cards with no prior use.
All groups then tried to build new three-item equivalence classes.
What they found
Only the picture group hit 100 percent class formation.
The other two groups scored far lower.
The old history of the cards mattered more than the extra training.
How this fits with other research
Arntzen et al. (2018) once showed that adding pictures plus a six-second delay tripled success.
The new study keeps the pictures but drops the delay and still wins big, hinting the pictures alone do the heavy lifting.
Austin et al. (2015) proved kids with autism can form equivalence across sound, touch, and sight.
McPheters et al. now show that for typical adults the choice of node picture, not disability status, drives the result.
Perez et al. (2020) found blocking the view of the right choice wrecks classes.
Together the two papers warn the same thing: tiny setup choices make or break equivalence.
Why it matters
When you plan equivalence lessons, pick pictures the learner already knows well.
Skip items that carry old instructional baggage.
One simple swap can turn a failed class into a perfect score.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Replace any reused flashcards with fresh photos the client can name instantly.
02At a glance
03Original abstract
The present study examined the effects of including stimuli previously trained as members of functional classes or equivalence classes on subsequent equivalence class formation, and isolated the effects of preliminary training from those of the acquired function stimuli. Fifty-six adults were assigned to 1 of 5 conditions. The control group (CONT) received no preliminary training prior to the terminal phase. Participants in the other 4 groups learned two 3-member functional classes and two 3-member equivalence classes during the preliminary phase. The terminal equivalence phase trained two 5-member classes (A → B → C → D → E) comprising abstract forms; the C stimuli in the terminal phase were (a) from the preliminary functional classes for 1 group (ACQ-F), (b) from the preliminary equivalence classes for the second experimental group (ACQ-E), (c) pictures of everyday objects for the picture control group (PIC), and (d) novel, unfamiliar stimuli for the preliminary training control group (PRE-CONT). Class formation yields were 100% in the PIC condition and 11% in the CONT condition; however, low yields in the PRE-CONT, ACQ-F, and ACQ-E conditions were unexpected, suggesting that procedural variables in preliminary training account for more of the subsequent effects on class formation than the stimulus control properties of the acquired function stimuli.
Journal of the Experimental Analysis of Behavior, 2021 · doi:10.1002/jeab.650