Mediation by intraverbal naming in children's equivalence test performance

Abstract

The mechanisms underlying stimulus equivalence are of considerable debate in the literature, especially regarding verbal behavior. The purpose of the present study was to evaluate Horne and Lowe's (1996) intraverbal naming hypothesis by investigating the effects of equivalence class formation on the emergence of novel intraverbals in six typically developing kindergarteners ages 4-6. Participants were first taught vocal tacts for pictures of states, birds, and flowers. Following tact training, they were exposed to MTS training in which they were first taught an A-B (i.e., state-bird) relation and an A-C (i.e., state-flower) relation and then exposed to an equivalence test probing 12 B-A, C-A, B-C, and C-B emergent intraverbal relations. Immediately following equivalence testing, an intraverbal test was conducted that probed intraverbal relations between the pictures (e.g., "Florida goes with which bird?"). Horne and Lowe predict that under those circumstances, participants who pass the equivalence test should also show a tendency to emit the relevant intraverbals. All three participants who passed the equivalence test passed the intraverbal test; however, two of those participants required additional rounds of both tests. Other participants passed a symmetry only test after requiring additional B-C training; only one of those participants passed the intraverbal test. Results suggest that verbal behavior may be necessary or have a substantial facilitative effect for performance on transitive relations, but unnecessary for performance on symmetrical relations. Implications for Horne and Lowe's (1996) analysis of intraverbal naming are discussed