The Neurocognition of Adult Second Language Learning: An fMRI Study

Abstract

Learners achieved very high proficiency in vocabulary and reasonably high proficiency in grammar, though morphosyntactic agreement was difficult to master. FMRI activation was found in areas associated with first language (L1) processing (e.g., BA45/47, and parietal cortex for lexical/semantics, and BA44 and 6 for grammar), suggesting that late-L2 learners have access to L1 regions. Additional areas were engaged, suggesting that L1 mechanisms are not sufficient for L2 learning and processing. At early stages of learning, hippocampal activation was found for both vocabulary and grammar. At later stages, basal ganglia activation was observed for grammar, particularly in the caudate nucleus. The findings suggest that early word and grammar learning relies on declarative memory (and more explicit processes), but that grammar later relies on procedural memory (and more implicit processes). These results highlight the utility of a mini-language model, have implications for neurocognitive theories of L2, and demonstrate the importance of integrating neural and behavioral methods in L2 research.