A number of studies have shown the possibility of using series of simple discriminations and multiple reversals to establish equivalent stimulus classes. The current study aimed to test the possibility of establishing equivalence classes through a training procedure that established simple discriminations on the basis of previously established ones, without reversals. Participants consisted of 6 children, aged 6 and 7. After the initial discrimination training of a pair of stimuli, two new, simple discriminations were established, one at a time, using the superimposition of stimuli. Following training, conditional relations between stimuli were tested. Results showed that all participants learned the discriminations almost without error: one participant had 6 errors and all the others had three errors or fewer. Tests for the emergence of classes of equivalent stimuli were positive for 3 participants and suggested the possibility of such emergence for 2 other participants.
Stimulus control; Discrimination; Conditioned stimulus