THE PHONOLOGICAL LOOP MODEL OF WORKING-MEMORY - AN ERP STUDY OF IRRELEVANT SPEECH AND PHONOLOGICAL SIMILARITY EFFECTS

The phonological loop model for retention of auditory verbal material in working memory, developed by Baddeley, assumes that irrelevant spee ch and phonological similarity influence only one and the same element of the system--that is, the phonological short-term store. We tested this idea by recording event- related potentials (ERPs) to auditorily presented letters that were phonologically similar or dissimilar and w ere to be memorized in the presence of more or less disturbing irrelev ant speech. Irrelevant speech and phonological similarity caused ERP e ffects with clearly different scalp topographies, indicating that thes e factors influence different brain systems and hence probably differe nt cognitive elements. More over, ERPs indicated that the phonological similarity effect might involve processes at the level of phonologica l analysis. Our data also support recent suggestions that the irreleva nt speech effect is not based on the phonological similarity between r elevant and irrelevant material, but on the phonological variability w ithin the irrelevant stream.