1 School of Psychology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada; Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada; Centre for Research on Brain, Language and Music, McGill University, Montreal, QC, H3G 2A8, Canada. Electronic address: skousaie@uottawa.ca.
2 Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada; Centre for Research on Brain, Language and Music, McGill University, Montreal, QC, H3G 2A8, Canada.
3 Centre for Research on Brain, Language and Music, McGill University, Montreal, QC, H3G 2A8, Canada; School of Communication Sciences and Disorders, McGill University, Montreal, QC, H3A 1G1, Canada.
4 Centre for Research on Brain, Language and Music, McGill University, Montreal, QC, H3G 2A8, Canada; Department of Psychology/Centre for Research in Human Development, Concordia University, Montreal, QC, H4B 1R6, Canada; Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research and Jewish General Hospital/McGill University Memory Clinic, Jewish General Hospital, Montreal, QC, H3T 1E2, Canada.
5 Centre for Research on Brain, Language and Music, McGill University, Montreal, QC, H3G 2A8, Canada; Department of Psychology, McGill University Montreal, QC, H3A 1G1, Canada.
6 Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada; Centre for Research on Brain, Language and Music, McGill University, Montreal, QC, H3G 2A8, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada.

A longstanding question in cognitive neuroscience and in the bilingualism literature is how early language experience influences brain development and cognitive outcomes, and whether these effects are global or specific to language-related processes. The current investigation examined the effect of the timing of language learning on the performance and neural correlates of phonological and non-verbal working memory, subcomponents of executive function. Three groups of bilinguals, who varied in terms of the timing of second language learning (i.e., simultaneous bilinguals learned their two languages from birth; early and late bilinguals who learned their second language before or after 5 years of age, respectively), performed phonological and non-verbal working memory tasks in the magnetic resonance imaging scanner. Results showed that there were no group differences in performance on either of the tasks, or in the neural correlates of performance of the non-verbal task. However, critically, we showed that despite similar behavioural performance, the groups differed in the patterns of neural recruitment during performance of the phonological working memory task. The pattern of group differences was non-linear, demonstrating similar neural recruitment for simultaneous and late bilinguals that differed from early bilinguals. Findings from the current study suggest a dynamic mapping between the brain and cognition, contributing to our current understanding of the effect of the timing of language learning on cognitive processes and demonstrating a specific effect on language-related executive function.