Considering definitions of stimulus equivalence

Establishing derived reinforcers via stimulus equivalence

If one of several stimuli in an equivalence class acquires a function, it transfers to all members of the respective class. Even though research has demonstrated this transfer across a variety of stimulus functions (e.g., discriminative), few studies have focused on the transfer of the reinforcing function. The current study extended previous literature by establishing derived reinforcers using conditional discrimination training with six neurotypical adults. We established three 4-member equivalence classes and then created a discriminative stimulus in one member by correlating it with reinforcement. We also expanded classes by adding a stimulus to each class and testing its function. During the transfer of function tests, five out of six participants chose the derived reinforcers more than the other stimuli. Three participants required remedial training or testing prior to demonstrating transfer of function. Results show that stimulus equivalence training is an effective and efficient paradigm to establish derived reinforcers.

Do common elements predict class merger: A test of Sidman's theory of equivalence

The study presented here investigated the effect of common and uncommon elements on class merger as predicted by Sidman in his reconceptualization of stimulus equivalence suggesting that common elements among contingencies can facilitate emergent performances (1994, 1997, 2000). Eight adult participants were exposed to a procedure that arranged for stimulus-reinforcer correlations in Phase 1 and response-reinforcer correlations in Phase 2 of a 3-phase study. In the common element group, the visual images serving as reinforcers were the same in Phase 1 and Phase 2. In the uncommon elements group, the images serving as reinforcers were different in Phases 1 and 2. In Phase 3, participants were given an opportunity to respond but no feedback was programmed. The results showed that participants' responding was well differentiated in the common element group and undifferentiated in the uncommon elements group. These results are predicted by Sidman's revised formulation of the provenance and scope of equivalence relations. Specifically, these data support Sidman's (1994, 1997, 2000) suggestion that elements of a contingency enter into an equivalence class and common elements among contingencies are sufficient to produce class mergers. The findings highlight an emergent simple discrimination and raise some interesting considerations about the definition of equivalence under the new formulation.