Phonological similarity effect is abolished by a silent mouthing task

This experiment was designed to examine the effect of silent mouthing on the phonological similarity effect. 16 undergraduates were tested for serial recall of visually presented letter sequences that were either phonologically similar or dissimilar. The letter sequences had to be remembered under two conditions, a control condition and a silent mouthing condition in which subjects had to articulate irrelevant words silently during the study period. Analysis showed the clear advantage of the dissimilar sequence over the similar one in the control condition. In contrast, this phonological similarity effect disappeared in the silent mouthing condition. This result is consistent with the working memory model.