Responding and Learning by Exclusion in 2-Year-Olds: The Case of Adjectives

Responding by exclusion, usually investigated using a baseline of auditory-visual conditional discriminations for which auditory samples are names, is a robust phenomenon; however, it lacks generality to other lexical word classes. This study had two purposes: (1) to assess the generality of learning by exclusion to word–object property relations, and (2) to evaluate the effect of additive exclusion trials on learning outcomes. Children (aged 24 to 29 months) were taught auditory-visual baselines for three object name–object relations (Noun condition) and/or three adjective (emotion) names–facial expressions relations (Adjective condition). Each baseline and its associated tests were presented sequentially; the order was counterbalanced across participants. After baseline performance met criterion, exclusion, control, and learning outcome trials in extinction were intermixed with reinforced baseline trials, and followed by additive reinforced exclusion trials and learning outcome tests. More trials to criterion were required to establish the Adjective baseline, but the exclusion and learning outcome results of both conditions were comparable, suggesting that responding and learning by exclusion have generality across stimulus (lexical) types. Additive exclusion trials increased learning outcomes, especially for one type of learning probe. The necessary and sufficient tests to determine learning outcomes of exclusion responding still deserve discussion and investigation.