You again? 14-month-olds show neural signatures of lexical-semantic activation for novel instead of familiar voices

We examined event-related potentials to determine whether familiar voices facilitate lexical-semantic processing in 14-month-olds. Particularly, we measured the N400 effect (greater negative-going amplitudes for semantic incongruences). Prior work suggests the importance of familiarity in infant cognition. Thus, we expected to find greater N400 effects for incongruent target words presented by a familiar as opposed to an unfamiliar voice. Infants were familiarized with one voice at home the week preceding the experiment. Brain activity of 30 monolingual infants was recorded while they listened to familiar and unfamiliar voices presenting audio-recordings of randomly ordered taxonomically related and unrelated word pairs. Participants showed a fronto-central N400 effect for the unfamiliar voice, and no difference between trial types for the familiar voice. This study provides novel evidence that 14-month-olds process taxonomic relatedness between spoken words without visual referents. Interestingly, infants of this age may be more engaged in language processing for unfamiliar voices.