The Relation Between Sorting Tests and Matching-to-Sample Tests in the Formation of Equivalence Classes

Abstract

Using the simultaneous protocol, 20 college students attempted forming three 5-member equivalence classes (A → B → C → D → E). In Group 1, baseline training was followed serially with a sorting test, a matching-to-sample (MTS) test of derived relations, and a second sorting test. In Group 2, baseline training was followed with an MTS test, a sorting test, and a second MTS test. In Group 1, initial sorting showed the immediate emergence of three classes for five, one, or two classes for three, and no classes for two participants, respectively. The MTS test documented equivalence classes for three of the first five, one of the next three, and none for last two participants, respectively. Across participants, 19 of 27 classes in sorting (70 %) predicted presence/absence of corresponding equivalence classes in MTS tests. For three participants in Group 2, initial MTS testing showed immediate emergence of all equivalence classes with their maintenance in follow-up sorting tests. Three others showed no classes in MTS testing and emergence of all during sorting, documenting delayed emergence of classes. The last MTS test documented equivalence for one of these three participants. Two others showed no class formation in any test. With five of 16 participants who showed class formation in sorting, the positioning of the stimuli in sorting reflected the nodal structure of the classes. Variables that should increase prediction of equivalence classes by sorting were discussed.