Expansion of arbitrary stimulus classes and function-transfer measured by sorting performances

Abstract

Sorting (SRT) and matching-to-sample (MTS) tests have measured the formation of arbitrary stimulus classes. This experiment used SRT and MTS tests to document the expansion of class size. Thirty-two participants learned 12 conditional discriminations with a linear series training structure (A➔B➔C➔D➔E). SRT tests documented the formation of 5-member classes by 17 of the participants. Thereafter, 6-member class expansion was implemented by FC training. Nine of these 17 participants showed class expansion when tracked with a sequence of an SRT, MTS, and a final SRT test, and the other 8 showed expansion when tracked with a sequence of MTS and SRT tests. Thus, SRT tests documented class expansion, and the sequence of tests did not influence class expansion. The 15 participants who did not form the 5-member classes learned the baselines for new 3-member classes (A➔B➔C) and formed them as documented by an SRT test. Then, 4-member class expansion was implemented by FB training. Expansion was assessed using the above-mentioned testing sequences. All 15 showed class expansion with 100% correspondence between the SRT and MTS performances. Sorting documented the expansion of arbitrary stimulus classes, while the MTS tests showed that the stimuli also functioned as members of equivalence classes.

Keywords: class expansion; matching-to-sample; meaningful stimuli; sorting; stimulus equivalence.