Training two severely retarded adolescents to ask questions.

Two retarded boys were taught to discriminate items they knew how to label (training items) from items they did not know (probe items), to respond appropriately by naming any training items, and to ask a question about any probe items. The boys did not learn to question when appropriate questioning was modelled by the experimenter; however, when they were prompted and rewarded for asking questions about some training items, they then began asking questions about probe items. Both the modelling-and prompting-reinforcement procedures were introduced in an across-subject, multiple baseline design.