High working memory load impairs selective attention: EEG signatures

According to the load theory of attention, increased working memory load impairs selective attention, resulting in greater distractor interference during inhibitory control processing. However, the EEG signatures correlated with this modulation effect of working memory on inhibitory control remain unclear. In present study, 25 healthy human participants performed a flanker task in a low and high working memory load conditions, while behavioral and electroencephalography (EEG) data were recorded. The results showed a larger reaction time interference effect while increasing working memory load, and this was accompanied by a larger N2 amplitude and a smaller P3 amplitude for incongruent trials. Time-frequency analysis revealed that, increased working memory load had no significant modulation effect on flanker related theta-ERS magnitude. Incongruent trials evoked smaller alpha-ERD magnitude than congruent trials in both low and high working memory load conditions. Increased working memory load was associated with larger flanker related alpha-ERD magnitude. Taken together, these results suggested that increased working memory load can impair top-down cognitive control processes, impairing inhibitory control processes during performance of the flanker task.