The Many Shades of Bilingualism: Language Experiences Modulate Adaptations in Brain Structure

Abstract

Recent years have seen an expansion in the research related to structural brain adaptations related to the acquisition and processing of additional languages. However, the accumulating evidence remains to a great extent inconsistent, with a large variety of cortical, subcortical, and cerebellar effects reported in various studies. Here we propose that the variability in the data can be explained by the differences in the language background and experiences of the tested samples. We also propose that the field should move away from monolithic bilingual versus monolingual comparisons; instead, it should focus on the experiences of the bilingual groups as predictors of structural changes in the brain, and also employ longitudinal designs to test the dynamic effects of active bilingualism. The implications of the proposed approaches for the suggested benefits of bilingualism on ageing and patient populations are also discussed.

Effect of Picture-Book Reading With Additive Audio on Bilingual Preschoolers’ Prefrontal Activation: A Naturalistic Functional Near-Infrared Spectroscopy Study

“…Future ecological research should consider the tasks of language production and comprehension together, especially for non-balanced bilingual children. Finally, given the latest direction in bilingualism study – i.e., that bilingualism is not a categorical label ( Luk and Bialystok, 2013 ) and should be regarded as a gradient or spectrum of the experience-based dynamic process ( Hernandez et al, 2018 ; DeLuca et al, 2019 , 2020 ; Pliatsikas, 2019 ; Pliatsikas et al, 2019 ; Sulpizio et al, 2020a ) – future studies on the effects of bilingualism on children’s brains should consider complex variables, ecological validity, and tracking paradigm.…”

Characterizing Bilingual Effects on Cognition: The Search for Meaningful Individual Differences

“…As we have noted, researchers have begun moving away from group comparisons between monolinguals and bilinguals, and instead are leveraging the diverse experiences represented within bilingual and multilingual populations e.g., [ 4 , 54 ] for reviews and commentaries on this issue, see [ 3 , 5 , 41 , 48 , 55 ]. In the sections that follow, we focus on the four issues we identified within the Pot et al (2018) study [ 45 ] that reflect these emerging issues.…”

“…Several models have been proposed linking various aspects of the bilingual experience with structural and functional neuroplasticity. These models include the Conditional Routing Model [ 68 ], the Adaptive Control Hypothesis [ 69 ], the Bilingual Anterior to Posterior and Subcortical Shift Model [ 70 ], and the Dynamic Restructuring Model [ 55 , 71 ]. Recently, DeLuca et al (in press) have proposed a theoretical framework called Unifying the Bilingual Experiences Trajectories (UBET) that integrates and builds upon the predictions of the four aforementioned models [ 72 ].…”

Beyond Alzheimer’s Disease: Bilingualism and Other Types of Neurodegeneration

“…As discussed above, bilingual language control inevitably aligns with domain-general executive control. If some executive functions are more engaged, potentially on a continuum related to bilingual practices such as density of code-switching (Green and Wei, 2016;Hofweber et al, 2016) or patterns of social language use (DeLuca et al, 2020), then this ubiquitous proverbial muscle-flexing over a sustained period of time could lead to the accruing of cognitive reserve and changes to neuroanatomical structure (opportunities for gains in neural reserve) (Pliatsikas et al, 2019). Effects at any point along the life-span continuum, different as their surface manifestations might seem, should, in principle, relate back to the same mechanisms and processes as above described.…”