Role of Distractors in Delayed Matching-to-Sample Arrangements in Tests for Emergent Relations

Some studies have presented math tasks as distractors in Delayed Matching-to-Sample (DMTS) procedures between the offset of the sample stimulus and the onset of the comparison stimuli in tests for equivalence class formation. The main findings have been a decrease in experimenter-defined correct matching performance when participants have been exposed to such distractors. Therefore, the purpose of two experiments in the present study was to extend the knowledge of how different types of distractors may or may not influence equivalence class formation in DMTS procedures. Experiments 1 and 2 were arranged as ABA designs. The A-phases were arranged without distractors and the B-phases with distractors during testing. In the test phases, dictation tasks were used as distractors in Experiment 1, while echoic tasks were used as distractors in Experiment 2. The results showed that matching accuracy and equivalence class formation were reduced in the B-phases but not in the A-phases in Experiment 1, while the echoic tasks did not influence performance in Experiment 2. The results are also discussed on the basis of the criterion of correct responding. Key words: stimulus equivalence, matching accuracy, delayed matching-to-sample, distractors