ABA Fundamentals

Reversal of baseline relations and stimulus equivalence: II. Children.

Pilgrim et al. (1995) · Journal of the experimental analysis of behavior 1995
★ The Verdict

Flip a baseline contingency and kids’ equivalence classes can crumble, so always re-probe.

✓ Read this if BCBAs teaching conditional discrimination or stimulus equivalence to young learners.
✗ Skip if Clinicians only running simple SR+ programs with no conditional matching.

01Research in Context

01

What this study did

Lerman et al. (1995) worked with five kids aged 5 to 7.

They taught the kids to match pictures in three-step classes: A→B, A→C.

After the classes formed, the team flipped the A→C rule so A now matched a new picture.

They then tested if the whole class shuffled or stayed the same.

02

What they found

Only two kids partly rebuilt the class.

The other three acted like the flip never happened.

In short, young kids’ equivalence networks cracked when the baseline rule reversed.

03

How this fits with other research

Lerman et al. (1995) also tested adults. Adults kept transitivity even after the same flip.

Same lab, same year, opposite outcome: kids collapsed, adults held.

Mace et al. (1990) saw the same adult pattern earlier.

McConkey et al. (1999) later showed preschoolers can reorganize classes, but only when you add extra steps.

Together the set says age and added training decide whether a class survives a reversal.

04

Why it matters

If you reverse contingencies in a conditional-discrimination program, probe every relation again. Kids may look like they mastered the new set, yet still respond to the old one. Build in quick symmetry and transitivity checks right after any rule change so you catch the crack before it spreads.

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After you change any matching rule, run two probe trials each for symmetry and transitivity in the next session.

02At a glance

Intervention
stimulus equivalence training
Design
single case other
Sample size
5
Population
neurotypical
Finding
mixed

03Original abstract

In a systematic replication of a study using college-student subjects (Pilgrim & Galizio, 1990), 5- to 7-year-old children learned two conditional discriminations (i.e., A1B1, A2B2, A1C1, and A2C2) in a two-choice arbitrary match-to-sample task and showed the emergence of two three-member equivalence classes (A1B1C1 and A2B2C2). Baseline conditional discrimination performance were quickly controlled by reversals of the AC reinforcement contingencies (i.e., choosing Comparison Stimulus C2 was reinforced given Sample A1, and choosing C1 was reinforced given Sample A2) when the reversals were introduced in restricted baselines. On reflexivity, symmetry, and transitivity/equivalence probes following the reversal, there was some limited indication of equivalence-class reorganization (i.e., A1B1C2 and A2B2C1) in keeping with the concurrently performed baseline relations for 2 of 5 subjects, but the predominant pattern across probe trials was one of inconsistent conditional control. These findings suggest that, given similar challenges, equivalence-class performances may be more easily disrupted in young children than in adults.

Journal of the experimental analysis of behavior, 1995 · doi:10.1901/jeab.1995.63-239