Beyond the bilingual advantage: The potential role of genes and environment on the development of cognitive control

Abstract

In recent years there has been considerable debate about the presence or absence of a bilingual advantage in tasks that involve cognitive control. Our previous work has established evidence of differences in brain activity between monolinguals and bilinguals in both word learning and in the avoidance of interference during a picture selection task. Recent models of cognitive control have highlighted the importance of a set of neural structures that may show differential tuning due to exposure to two languages. There is also evidence that genetic factors play a role in the availability of dopamine in neural structures involved in cognitive control. Thus, it is important to investigate whether there are interactions effects generating variability in language acquisition when attributed to genetic (e.g., characteristics of dopamine turnover) and environmental (e.g., exposure to two languages) factors. Here preliminary results from genotyping of a sample of bilingual and monolingual individuals are reported. They reveal different distributions in allele frequencies of the DRD2/ANKK1 taq1A polymorphism. These results bring up the possibility that bilinguals may exhibit additional flexibility due to differences in genetic characteristics relative to monolinguals. Future studies should consider genotype as a possible contributing factor to the development of cognitive control across individuals with different language learning histories.

Individual differences in the bilingual brain: The role of language background and DRD2 genotype in verbal and non-verbal cognitive control

“…The findings that A1 carrier status predicts neural activity in the left IFG during English picture naming and the ACC during non-verbal task switching suggest that understanding genetic differences across populations is important. Hernandez and colleagues (2015) found, using pilot data, that Spanish-English bilingual university students carry the A1 allele at twice the rate of the English monolinguals studied. If the genetic variation is an important source of individual differences and affects neural activity, as suggested by the results of the current study, then it may be incorrect to assume that the difference between bilinguals and monolinguals in neural activity is caused solely by differing language experiences.…”

“…The current study takes an interdisciplinary approach to examine the role of the genetic background and bilingual experience in predicting fMRI activity during language control and cognitive control tasks. This study follows up on preliminary evidence from Hernandez, Greene, Vaughn, Francis, and Grigorenko (2015), which suggests that there may be important genetic variation between groups of Spanish-English bilinguals and English monolinguals.…”

“…Hernandez and colleagues (2015) pointed out that Spanish-English bilinguals may differ from their monolingual peers in the frequency distribution of the genotypes of the DRD2 /ANKK1 Taq1A polymorphism. The Spanish-English bilingual group in Hernandez and colleagues’ sample contained twice as many carriers of the A1 allele than the English monolingual sample.…”

“…Therefore, when studying the role of this genetic variant in neural activity, it is important to control for race and ethnicity. The previous study by Hernandez and colleagues (2015) compared a group of Hispanic bilinguals to a group of Caucasian, non-Hispanic monolinguals. The ethnic difference between these two groups is a potential explanation for the differing distributions of genotypes in the sample (i.e., more A1 carriers than non-carriers in the bilingual sample and the reverse pattern in the monolingual sample).…”

The importance of neuroscience in understanding bilingual cognitive control

“…For example, findings from our lab at the University of Houston suggest that there may be genetic differences between college-aged Spanish-English bilinguals and English monolinguals. In our sample, bilinguals carried the A1+ allele of the ANKK1 gene in higher proportions than monolinguals (Hernandez et al, 2015). The A1+ allele has been previously shown to be related to better cognitive control performance, and different recruitment of the inferior frontal gyrus during task-switching (Stelzel et al, 2013).…”