Emergence of a three-sample conditional discrimination as foundation for reasoning capabilities.

We hypothesized that a three-sample conditional discrimination can emerge as a result of learning conditional discriminations with relational stimuli. After learning three first-order conditional discriminations AB, PQ, and CD, we taught a second-order conditional discrimination XAB in which X1 indicated selection of related stimuli (e.g., A1 and B1) and X2 of unrelated stimuli (e.g., A1 and B2). Then, we probed the emergence of conditional discriminations PQX and XCD in which the X stimuli were comparisons and contextual stimuli, respectively. Finally, a conditional discrimination was probed with stimuli P, Q, and C as samples and D1 and D2 as comparisons. When the P and Q stimuli were related (and related to X1 in PQX), all participants selected the D stimulus that was related to the C stimulus (D1 when C1 was present and D2 when C2 was present); when the P and Q stimuli were unrelated (and related to X2 in PQX), they selected the D stimulus unrelated to the C stimulus (D2 when C1 and D1 when C2), which demonstrated emergence based on the relations established among all stimuli. In Experiment 2, the teaching of XAB was omitted and only one in six participants demonstrated emergence, which indicated that relational stimuli X1 and X2 played an important role in emergence. Thus, a new type of emergence that mimics analogical reasoning was demonstrated. The obtained outcome suggests that this procedure provides a learning foundation for acquiring reasoning capabilities.