Becoming a balanced, proficient bilingual: Predictions from age of acquisition & genetic background. (May 2018)

• Record Type: Journal Article
• Authors: Vaughn, Kelly A.; Hernandez, Arturo E.
• Is Part Of: Journal of neurolinguistics. Volume 46(2018)
• Page Start: 69
• Page End: 77
• Publication Date: 2018-05
• Subjects: Bilingualism -- Proficiency -- DRD2 -- COMT; Neurolinguistics -- Periodicals; Language and languages -- Physiological aspects -- Periodicals; Psycholinguistics -- Periodicals; Brain -- physiology -- Periodicals; Language -- physiology -- Periodicals; Neurolinguistique -- Périodiques; Langage et langues -- Aspect physiologique -- Périodiques; Psycholinguistique -- Périodiques; Language and languages -- Physiological aspects; Neurolinguistics; Psycholinguistics; Periodicals; Electronic journals; 616.855
• DOI: 10.1016/j.jneuroling.2017.12.012
• Languages: English
• ISSNs: 0911-6044

Abstract

Abstract: Genetic variants related to dopamine functioning (e.g., the ANKK1/TaqIa polymorphism within the DRD2 gene and the Val158Met polymorphism within the COMT gene) have previously been shown to predict cognitive flexibility and learning (e.g., Colzato et al., 2010; Stelzel et al., 2010). Additionally, researchers have found that these genetic variants may also predict second language learning (Mamiya et al., 2016), although this relationship may change across the lifespan (Sugiura et al., 2011). The current study examined the role of the ANKK1/TaqIa and Val158Met polymorphisms along with age of second language acquisition (AoA) in order to predict levels of bilingual proficiency in Spanish-English bilinguals. Results indicated a three-way interaction such that the relationship between the genetic variants and bilingual proficiency depended on AoA. At earlier AoAs, having the genetic variant associated with higher levels of subcortical dopamine (A1+) predicted the highest levels of bilingual proficiency. At later AoAs, individuals with the genetic variant associated with cortical dopamine levels that are balanced between stability and flexibility (Val/Met) predicted the highest levels of bilingual proficiency. These results fit with theories about the development of language as a subcortical process early in life and as a cortical process later in life (Hernandez & Li, 2007), as well as the importance of both stability and flexibility in bilingual language development (Green & Abutalebi, 2013). Finally, this study raises questions about the direction of causality between bilingualism and cognitive control, which is central to the debate over the "bilingual advantage." Highlights: Spanish-English bilinguals were genotyped for ANKK1/TaqIa and Val158Met SNPs. Early bilinguals with the A1+ genotype achieved high proficiency. Late bilinguals with the Val/Met genotype achieved high proficiency. Becoming a proficient bilingual early in life is related to subcortical dopamine. Becoming a proficiency bilingual later in life is related to cortical dopamine.