Plasticity of the Language Network Underpins Children's Greater Short-term Linguistic Learning Efficiency than Adults

Language learning appears to become more effortful and less efficient across the lifespan, but what explains this change remains unresolved. This study addressed this question by directly examining the learning processes. In two experiments, children and adults completed a linguistic (Syllable) implicit learning task and a nonlinguistic (Tone) control task. In both tasks, participants heard continuous auditory streams containing trisyllabic or three-tone “words”. Learning was measured via reaction time acceleration to predictable items and by neural responses to structured versus random streams within language regions identified via an independent story-listening task. Children showed faster learning than adults only in the linguistic learning task. fMRI revealed earlier and stronger learning-induced plasticity in children’s language network than adults. Greater neural sensitivity was further associated with faster linguistic learning in children, but not in adults. These findings suggest that children’s developing language network is especially well suited to efficiently acquire new linguistic inputs.