Yusuke MoriguchiKanda LertladaluckMahidol UniversityGraduate School of Education2020-01-272020-01-272019-01-01International Journal of Bilingualism. (2019)17566878136700692-s2.0-85074333646https://repository.li.mahidol.ac.th/handle/20.500.14594/49988© The Author(s) 2019. Aims and objectives: Bilingual children constantly experience spontaneous switching between languages in everyday settings, and some researchers suggest that this experience leads to an advantage in task performance during executive function tasks. Neural processing during executive function tasks remains largely unknown, especially in young bilingual children. Methodology: Using functional near-infrared spectroscopy, this study examined whether young children who attended an immersion second-language program demonstrated enhanced cognitive shifting and lateral prefrontal activation. Data and analysis: We recruited children (N = 24) who attended an international nursery school, and examined whether their performance on cognitive shifting, and whether the oxygenated hemoglobin changes in the prefrontal regions during the task, were correlated with the children’s second-language verbal age and the length of time the children had been speaking the second language. Findings: Results revealed that the verbal age of the second language and the length of time speaking it were significantly correlated with behavioral performances of cognitive shifting tasks. However, they were not correlated with the activations in the lateral prefrontal regions. Originality: We examined the neural correlates of bilingual effects on cognitive shifting and prefrontal activations in young children. Implications: The results suggest that second-language experience may not be directly related to neural processing in the lateral prefrontal cortex, at least in young children.Mahidol UniversityArts and HumanitiesSocial SciencesArticleSCOPUS10.1177/1367006919880274