Relations between baseline contingencies and equivalence probe performances.
Equivalence classes can keep their transitive links even after you flip the baseline payoffs, so probe both symmetry and transitivity before you trust the class is gone.
01Research in Context
What this study did
The team taught adults to pick the correct picture when they saw a sample.
After the matches were solid, they flipped the rules.
Now the old correct choice paid off zero.
They then tested symmetry (A-B and B-A) and transitivity (A-C through B) to see what survived the flip.
What they found
Symmetry probes fell apart for most people.
Transitivity probes kept hugging the original classes.
Equivalence, once born, partly ignores the new pay table.
How this fits with other research
Lerman et al. (1995) ran the same flip with adults and saw the same split: symmetry broke, transitivity held.
Lerman et al. (1995) later tried the flip with 5- to 7-year-olds and got a messier picture—only two kids partly reorganised.
Together the three papers show age matters: adult equivalence is sticky, kid equivalence is brittle.
Perez et al. (2020) found that blocking the view of the correct choice also hurt transitivity.
Both studies tell us transitivity is the fragile flower—protect it from rule changes or blocked looks.
Why it matters
If you reverse teaching contingencies mid-stream, do not trust symmetry probes alone.
Keep testing transitivity to be sure the class still hangs together.
With children, plan for full retraining after any switch; their classes collapse faster than those of teens or adults.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →After you change which comparison earns points, run fresh transitivity trials; if they pass, your class is still alive even if symmetry looks shaky.
02At a glance
03Original abstract
Following the emergence of two three-member equivalence classes (A1B1C1 and A2B2C2), 5 college students were exposed to one or more changes in the reinforcement contingencies controlling baseline conditional discriminations. AC relations were either reversed (i.e., C2 was reinforced and C1 punished when A1 was the sample; C1 was reinforced and C2 punished when A2 was the sample) or arranged randomly (i.e., C2 and C1 were reinforced and punished equally often in the presence of A1 and A2). In a third condition, the original AB and AC relations were reversed. Results showed that although baseline conditional discrimination performances were under the control of reinforcement contingencies, and performances on symmetry trials varied with baseline responding for 3 of 4 subjects when contingencies were reversed, performances on transitivity probes remained consistent with the initial equivalence class. These inconsistencies between probe and baseline performances were striking because conditional discriminations are thought to be the determinants of equivalence class performance. Similarly, the contrast between performances on symmetry and transitivity probes was of theoretical interest because equivalence classes are defined by congruent patterns of responding on probe trials.
Journal of the experimental analysis of behavior, 1990 · doi:10.1901/jeab.1990.54-213