Carpentier, Smeets, & Barnes-Holmes, 2002

The article provides information on studies that examined whether, following conditional discrimination training with unitary stimuli (A-B and P-Q), procedures that had been successfully used for training the AB-X relations and testing transfer (PQ-X) in older children and adults would be appropriate for preschoolers. Most children did not learn AB-X tasks unless they were first trained to respond to all compound elements, and they did not reliably show transfer unless they had first learned that the compounds represented sample comparisons relations.