Formation of new stimulus equivalence classes by exclusion

Emergence of Third-Order Conditional Discriminations from Learning Discriminations with Unrelated Stimuli

This study explored learning and generalization of a third-order conditional discrimination. Two 8-year-old children learned two auditory–visual conditional discriminations in which they selected visual Japanese syllabic symbols in response to syllables spoken by the experimenter. Then, they learned a third-order conditional discrimination in which they selected between two visual symbols after being exposed to two spoken syllables and one visual symbol. Thereafter, we probed generalization with novel symbols and names by teaching two additional conditional discriminations with Nahuatl symbols and spoken words and probing without reinforcement a new third-order conditional discrimination in which they had to select between two visual Nahuatl symbols after being exposed to two spoken Nahuatl words and one visual Nahuatl symbol. The two children responded in a predicted way to the novel third-order conditional discrimination. The emergent performance was possible because the set of relations established among the stimuli of the third-order conditional discrimination with Japanese syllables was analogous to the set of relations established among the stimuli of the third-order conditional discriminations with Nahuatl words. These results demonstrated a novel type of emergent responding in third-order conditional discrimination with arbitrary relations.

Children's emergent relations of equivalence using stimuli with opposite verbal labels: Exclusion and minimal training conditions

The present study examined different conditions under which exclusion responding in conditional discrimination tasks would generate emergent equivalence relations in young children based on shared relationships with verbal labels. Both visual stimuli (Sets A, B, C, and D) and auditory stimuli (spoken words, Set N: N1 "correct"; N2: "incorrect") were used. Following a pilot study, three experiments were conducted, each involving eight preschool children. These experiments systematically investigated under which conditions responding by exclusion (i.e., responding away from a designated S^- comparison in a matching to sample context) would generate sufficiently stable sample-S⁺ relations for arbitrary stimulus classes to establish. The results showed that young children's exclusion responding under test conditions will only contribute to arbitrary stimulus class formation and expansion when training has already established two arbitrary stimulus classes involving at least two stimuli each. For young children to demonstrate emergent conditional discrimination performances that are indicative of the formation of equivalence relations, it is necessary to have training and/or reinforced exposure to both S⁺ and S^- control elements required for deriving the appropriate emergent relations with at least two conditional relations involving different samples. These findings not only contribute to existing research and theory on the conditions under which exclusion responding may contribute to fundamental language and learning processes, they also contribute to the experimental predictability of emergent conditional matching behaviours in preschool children by further unravelling the conditions under which emergent matching based on exclusion generates arbitrary conditional relations of equivalence.

Transfer of baseline reject control to transitivity trials and its effect on equivalence class formation

This study explored the role of baseline reject control on transitivity responding. In Experiment 1, participants learned to respond to a baseline of arbitrary AB and AC conditional relations, and then they were exposed to transitivity-like BC and CB trials in which the correct comparison stimulus was replaced by a novel stimulus (D). Five of 10 participants selected stimulus D, but only 1 showed expansion of the baseline stimulus classes to include the D stimuli. In Experiment 2, the emergence of symmetry and transitivity from baseline relations was assessed before participants were exposed to the transitivity-like trials. Six of 8 participants who showed emergence of equivalence relations selected the D stimuli on transitivity-like trials and provided evidence that baseline classes expanded to include these stimuli. In Experiment 3, these 6 participants selected novel stimuli (E) in additional transitivity-like trials, and all showed that the E stimuli had become members of the previously established classes, which now comprised 5 members. A route for the emergence of transitivity by way of the transfer of baseline between-classes reject control is discussed.