High Probability of Equivalence Class Formation with Both Sample-S+ and Sample-S- Controlling Relations in Baseline

Abstract

In this study, 4 school children learned AB, BC, and CD matching relations between three samples and three comparisons. In Condition A, which attempted to ensure development of both sample-S+ and sample-S- controlling relations, trials displayed the sample, the mask, and one comparison (either the S+ or 1 of the possible S-s). Condition B attempted to prevent development of sample-S+ relations in the BC conditional discrimination. It was similar to Condition A except that trials for relation BC always displayed the sample, mask, and S-. Results showed a high probability of equivalence class formation when the structure of trials ensured sample-S+ and sample-S- controlling relations in baseline. Equivalence classes were not formed when sample-S+ relations were prevented in one of the baseline relations. This study confirms previous results suggesting that stimulus equivalence is more probable when the baseline guarantees both sample-S+ and sample-S- relations.