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Poster E10, Friday, November 10, 10:00 – 11:15 am, Harborview and Loch Raven Ballrooms

Becoming a balanced, proficient bilingual: Predictions from age of acquisition & genetic background

Kelly A. Vaughn1, Arturo E. Hernandez1;1University of Houston

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 young adult bilinguals. The ANKK1/TaqIa polymorphism is located within the DRD2 gene, and codes for D2 dopamine receptors that are found subcortically. Individuals with the A1+ genotype (i.e. carrying at least one A1 allele) compared to individuals with the A1- genotype (i.e., carrying no A1 alleles) show a reduction in D2 receptors, which leads to increased subcortical dopamine (Laakso et al., 2005), and greater flexibility during cognitive tasks (Stelzel et al., 2010). The Val158Met polymorphism is located within the COMT gene, and is related to the breakdown of prefrontal dopamine. The polymorphism has three genotypes, Val/Val, Val/Met, and Met/Met. Each Met allele is related to increased prefrontal dopamine (Chen et al., 2004), and decreasing flexibility but increasing stability during cognitive task performance. Bilingual proficiency was calculated as the sum of proficiencies in English and Spanish based on the Woodcock-Muñoz Language Survey - Revised (Woodcock, Muñoz-Sandoval, Ruef, & Alvarado, 2005), multiplied by a number that represented the amount of balance between the two languages. This led to a measure of bilingual proficiency that gave a slight boost to individuals who are more balanced in their proficiency in English and Spanish. Data was analyzed using a multiple regression model that included the two genotypes and AoA and controlled for socioeconomic status. 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 (Chandrasekaran, Koslov, & Maddox, 2014; 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." Most studies regarding a bilingual advantage in cognitive tasks suggest that bilingualism influences cognitive control outcomes. The results of the current study provide an alternative to this perspective, suggesting instead that genetic variants associated with dopamine and cognitive flexibility may influence language proficiency outcomes.

Topic Area: Language Genetics

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