The effects of response topography on functional equivalence class formation

To examine the transfer of function phenomenon two 3-member equivalence classes were established using the typical selection response of key pressing (A1, B1, C1, & A2, B2, C2). One 3-member class was then made functionally equivalent by training a topographically distinct response (clapping) to Al and obtaining clapping at B1 and C1. Five experiments examined the effects of adding a new function (stamping) to members of this original functional equivalence class. In Experiment 1 a new function was added to a three-member functional equivalence class by training it to a stimulus other than where the original function trained. The results indicated that for adults and 12-year-old children the new function transferred to all original class members. However, for two 6-yr-old children the new function did not transfer to all class members. Experiments 2, 3, 4, and 5 were conducted exclusively with children who were approximately 6 years old and addressed issues arising from the findings of Experiment 1. Specifically, these experiments investigated the effects of the number of presentations of the stimuli in the transfer of function testing stage, where the new function was trained in relation to the original function, when the function was trained in relation to the actual equivalence training, and how the functions were trained. The general finding was that the new function rarely transferred to all members of an established three-member functional equivalence class for children who were approximately 6 years old, unless the new function was trained to the stimulus where the original function was trained. These findings may have relevance to the debate on both the constitution of class membership and contextual control of equivalence responding.