Long-term memory for voices frees up cognitive resources and enhances speech perception in noise

When masked by competing speech, utterances are more intelligible when spoken by a familiar voice than by a novel one. If familiar voices are less cognitively demanding to perceive, a concurrent task, which consumes resources, should disrupt perception of speech less if the attended voice is familiar. Furthermore, if the intelligibility benefit occurs because listening to a familiar voice is less cognitively demanding, then the concurrent task should reduce the familiar voice benefit. Participants (N=30) heard two concurrent closed-set sentences in two different voices (familiar-novel or novel-novel) and reported the content of one (target) while ignoring the other (masker). Simultaneously, participants tracked the location of four moving dots on a screen (multiple object tracking, dual task) or ignored the visual input (single task). Word report was highest when the target voice was familiar, lowest when the masker voice was familiar, and intermediate when both voices were novel. Concurrent MOT performance reduced intelligibility of the novel, more than the familiar, voice, but did not reduce the magnitude of the benefit, suggesting that familiar voices require fewer cognitive resources to process than unfamiliar ones but that this reduction may not directly facilitate the familiar-voice benefit.