Additional tasks in a Delayed Matching-to-Sample procedure

Dictation tasks and echoic tasks were introduced in a delayed matching-to-sample procedure in two experiments, respectively. In both experiments, the participants were tested for equivalence class formation. Furthermore, in a third experiment, dictation tasks were also introduced when the conditional discriminations were established, without introducing symmetry or equivalence trials. The results showed that the dictation tasks as an additional task in the first experiment reduced equivalence class formation, while the echoic task in the second experiment did not affect responding in accordance with stimulus equivalence as the dictation tasks in the first experiment. In the third experiment the conditional discriminations were affected by the additional task, but not to the same degree as in the first experiment.