The influence of training procedure and stimulus valence on the long-term maintenance of equivalence relations

In the current research, we aimed at extending Silveira et al. (2016) results by verifying whether the long-term maintenance of the equivalence classes is influenced by stimulus valence and MTS training procedures. The delayed and simultaneous MTS were used to train two groups of participants in series of conditional relation trials involving pictures of humans' faces expressing familiar emotions (A) and abstract forms (B, C, and D). The participants that demonstrated the emergence of novel BD and DB relations and class-consistent derived transfer of functions returned to the laboratory thirty days later. Follow-up assessments were given in which the probability of class-consistent responses was higher for the happy class only for participants exposed to DMTS training. This result shows that the maintenance of equivalence classes cannot be accounted for only in terms of the affective valence of the familiar stimulus. The affective valence of the happy faces may have yoked with the properties of DMTS, favoring the maintenance of the happy class. Thereby, we discussed the role of mediating verbal behavior evoked selectively by the pictures of happy faces appearing as samples that may have persisted during the delay interval as a possible mechanism underlying performances of participants trained in DMTS procedure.