ABSTRACT
In the 1970s, Barbara Etzel and colleagues developed visual stimulus-manipulation procedures for better teaching, based on earlier procedures labeled stimulus shaping by M. Sidman and T. Stoddard. Stimulus shaping involves familiar initial stimuli composed of many dimensionally different elements that are easy to discriminate. Stimulus shaping always emphasizes an element in each of the stimuli that changes little across learning trials, is emphasized during the shaping process, and forms the basis on which the final, more difficult, discrimination can be made. B. C. Etzel and colleagues' stimulus shaping was designed to avoid problems of transfer from initial stimulus elements to criterion stimulus elements. Both meaningful and nonmeaningful programs used a criterion-related cue, that is, an initial stimulus element that continued to be present during and after the shaping of the initial entry-level stimuli.
