Effects of subvocal suppression, articulating aloud and noise on sequence recall

Subjects were required to reproduce in order a sequence of five letters; the set of letters was known so only memory for sequence was tested. Experiment 1 showed that suppressing subvocal rehearsal by saying 'the' continously during list presentation and until recall depressed performance to the same level on acoustically confusable and non-confusable lists. Listening to 85 dBC white noise during list presentation improved performance on acoustically confusable lists in non-suppression conditions and had no effect in suppression conditions. The result refutes the hypothesis that noise suppresses inner speech. Expts 2, 3 and 4 showed that articulating the items aloud during list presentation and until recall improved performance when lists were presented at 1/2 s per item and depressed it when they were presented at 2 s per item. Improvement occurred under 85 dBC white noise in Expts 2 and 4, but the improvement was only significant in non-articulation conditions. It is suggested that noise increases subvocal articulation and that both noise and articulation increase maintenance rehearsal at the expense of elaboration rehearsal.