Conditional discrimination after errorless and trial-and-error training.
Begin conditional discrimination training with stimulus shaping—prior trial-and-error or fading can block later learning even after you switch methods.
01Research in Context
What this study did
Foster et al. (1979) compared three ways to teach conditional discrimination to preschool and early-elementary kids.
One group learned through stimulus shaping: the correct picture slowly appeared while the wrong one faded out.
A second group got stimulus fading: both pictures stayed visible, but the right one got brighter.
The third group learned by trial-and-error: they guessed until they got it right.
What they found
Kids who started with shaping mastered the task fastest and made almost no errors.
Kids who began with fading or trial-and-error later struggled even when switched to shaping.
Early errors seemed to lock in wrong rules, slowing new learning later.
How this fits with other research
Fantino (1968) showed the same pattern with simple position tasks in boys with severe ID: graduated prompting beat trial-and-error.
Frederiksen et al. (1978) found that first-graders who first learned through trial-and-error made more errors later during reversal tasks.
Together these studies form a line: errorless starts protect future learning, while early errors create persistent trouble.
Schneider et al. (1967) already showed fading topped trial-and-error for form discrimination; L et al. extend the advantage to harder conditional tasks.
Why it matters
Start every conditional discrimination program with stimulus shaping, not fading or trial-and-error.
If a learner has already failed with trial-and-error, expect slower progress when you switch methods; you may need extra practice to break the old error pattern.
This single switch can cut acquisition time and leave a cleaner learning history for future tasks.
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02At a glance
03Original abstract
Children were trained on a visual discrimination by stimulus shaping, stimulus fading, or trial-and-error. Those who did not acquire the conditional discrimination received a second, different training. More children initially trained by stimulus shaping acquired the conditional discrimination than did those initially trained with stimulus fading or trial-and-error. After a history of fading or trial-and-error training, children were less likely to acquire the conditional discrimination even after the more successful procedure of shaping was later used.
Journal of the experimental analysis of behavior, 1979 · doi:10.1901/jeab.1979.31-405