Short-term forgetting and the articulatory loop

Two experiments explored the role of subvocal articulatory rehearsal in the Peterson short-term forgetting task. In the first of these, subjects recalled consonant trigrams after an interval of o, 5 or 15 s during which they either counted backwards in threes, suppressed articulation by continuously uttering the word “the”, or in a third control condition continuously tapped on the table. While counting backwards caused the usual dramatic forgetting, tapping caused no forgetting, and articulatory suppression only minimal forgetting at the longest delay. A second study used the same procedure but included only two conditions, articulatory suppression during the retention interval and articulatory suppression during both input and retention. Neither showed evidence of forgetting over the 15 s delay. These results suggest that covert speech is not necessary for rehearsal in short-term verbal memory. As such they call for a re-evaluation of the nature and function of rehearsal.