A Comparison of Stimulus Fading and Stimulus Shaping on Perceptual Category Learning

Errorless learning strategies such as stimulus fading and stimulus shaping are commonly used to teach complex skills like categorisation and concept formation. Despite widespread use, very few studies have explored the comparative effectiveness of these procedures in well controlled analyses. The vast majority of studies have been undertaken with clinical populations and have involved small numbers of participants (e.g., Single-case designs). The present study sought to extend recent work by Pashler and Mozer (2013) on the effectiveness of stimulus shaping by comparing stimulus fading, stimulus shaping and trial-and-error learning in a perceptual categorisation task. In Experiment 1, we found robust benefits of stimulus shaping when compared to stimulus fading or trial and error learning on measures of initial acquisition of discrimination and a measures of stimulus generalisation. These findings were replicated in a second experiment in which the dimension of fading/shaping was changed from the adaptation of the comparators (S-) to the adaptation of the target stimulus (S+). We discuss the implication our findings in relation to the selection of errorless learning strategies in clinical settings.