Disruption of short-term memory by unattended speech: Implications for the structure of working memory

Abstract

A series of experiments studied the effect of unattended speech on immediate memory for visually presented digits. Memory performance showed clear impairment, with the degree of impairment being a function of the phonological similarity of the irrelevant words to the visually presented digits. In contrast, the semantic characteristics of the unattended speech did not influence performance. Requiring the subject to suppress articulation removed the disrupting effect of irrelevant speech. These results are interpreted in terms of two separate memory systems of which one relies on a phonological code. The system is accessible in two ways, through auditory presentation leading to obligatory registration of the material, or through an optional subvocal rehearsal process.