Matching unrelated stimuli with same discriminative functions: training order effects.

Previous research has shown that after training simple discriminations (A1+/A2-, B1+/B2-), bringing these tasks under conditional control (J1-A1, J2-A2) leads to transfer of discriminative control (J1+/J2-) and to generalized matching on the basis of same discriminative functions (e.g. J1-B1, J2-B2). The same occurs when conditional discriminations are trained (D1-E1, D2-E2; F1-G1, F2-G2). When the subjects are then trained to demonstrate correct relations (D1-E1, D2-E2) when given X1 and to demonstrate incorrect relations when given X2 (XD-E), transfer of discriminative control (X1+/X2-) and generalized matching on the basis of same discriminative functions emerges (e.g. X1F1-G1, X2F1-G2). The present study investigated if these performances are dependent on the training and/or testing order. In Experiment 1, the lower-order contingency tasks were trained before the higher-order contingency tasks (A1+/A2-, B1+/B2- before J-A, and D-E, F-G before XD-E). Half the subjects received the J-B test before the more complex XF-G test (Condition A), while for the other subjects, this testing order was reversed (Condition B). Finally, all subjects received additional tests in which they were given the opportunity to demonstrate the discriminative properties of the J and X stimuli (J1+/J2-, X1+/X2-), and to match the A, J, and X stimuli with newly introduced stimuli of same discriminative properties (e.g. J1-POLITE, J2-RUDE). Experiment 2 was the same except that the training order was reversed (J-A before A1+/A2-, B1+/B2-, and XD-E before D-E, F-G). The results were affected by the training order but not by the testing order. Transfer of discriminative functions and generalized matching on the basis of same functions only occurred reliably when the lower-order contingency tasks were trained first. A stimulus-control account of the data is offered.