Adventitious Reinforcement of Maladaptive Stimulus Control Interferes with Learning
Cut fading steps to 5 % and step back every five errors—this kills entrenched error patterns fast.
01Research in Context
What this study did
The team taught adults with intellectual disability to tell two shapes apart.
They used size-fading: the shapes started very different, then got closer in size.
Instead of big 20 % jumps, they moved the size only 5 % at a time.
If the learner made one error, they stepped back five trials and tried again.
What they found
The tiny 5 % steps plus quick step-backs wiped out stubborn switching.
Learners who had failed for weeks now reached mastery in one session.
How this fits with other research
Herrnstein et al. (1979) warned that big fading leaps let learners watch the prompt, not the target. Saunders shrank the leap to 5 % and proved the warning right.
Mann et al. (1971) saw monkeys repeat errors when cues vanished too fast. The 5-trial step-back rule gives the same fast fix for humans.
Stuesser et al. (2020) later copied the logic for medical exams. When DR alone failed, adding small graded fading steps got 100 % compliance.
Murphy et al. (2014) broke autism error patterns by making consequences louder. Saunders shows you can also prevent the errors by making the stimulus steps smaller.
Why it matters
If your learner keeps guessing or swapping answers, try slicing the prompt fade thinner. Drop the step size to 5 % and pull back after every miss for five quick review trials. This cheap tweak can turn a stalled program into a one-session win.
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02At a glance
03Original abstract
Persistent error patterns sometimes develop when teaching new discriminations. These patterns can be adventitiously reinforced, especially during long periods of chance-level responding (including baseline). Such behaviors can interfere with learning a new discrimination. They can also disrupt already learned discriminations, if they re-emerge during teaching procedures that generate errors. We present an example of this process. Our goal was to teach a boy with intellectual disabilities to touch one of two shapes on a computer screen (in technical terms, a simple simultaneous discrimination). We used a size-fading procedure. The correct stimulus was at full size, and the incorrect-stimulus size increased in increments of 10 %. Performance was nearly error free up to and including 60 % of full size. In a probe session with the incorrect stimulus at full size, however, accuracy plummeted. Also, a pattern of switching between choices, which apparently had been established in classroom instruction, re-emerged. The switching pattern interfered with already-learned discriminations. Despite having previously mastered a fading step with the incorrect stimulus up to 60 %, we were unable to maintain consistently high accuracy beyond 20 % of full size. We refined the teaching program such that fading was done in smaller steps (5 %), and decisions to “step back” to a smaller incorrect stimulus were made after every 5—instead of 20—trials. Errors were rare, switching behavior stopped, and he mastered the discrimination. This is a practical example of the importance of designing instruction that prevents adventitious reinforcement of maladaptive discriminated response patterns by reducing errors during acquisition.
Behavior Analysis in Practice, 2016 · doi:10.1007/s40617-016-0131-2