Four severely retarded preschool children were taught to label four objects using a manual, direct select communication board. After acquisition, learners failed to generalize to either commenting or requesting using the trained vocabulary. It was hypothesized that learners failed because (a) they had never learned to request using their newly acquired vocabulary or (b) because the production of object labels was only under control of the verbal stimulus "What's this?" A second experiment, designed to test these hypotheses, suggested that teaching a pragmatic discrimination between requesting and object labeling resulted in improved performance for two learners. A procedure to shift stimulus control from a verbal cue ("What's this? ") to the presence of the object improved performance on spontaneous probes for a third learner. The remaining learner failed to acquire the spontaneous use of the acquired vocabulary.
Verbal Stimulus Control and the Intraverbal Relation
