Socioeconomic Disparities in the Structure of Language Areas in the Developing Brain

Socioeconomic disparities in childhood are associated with remarkable differences in cognitive and socio-emotional development during a time when dramatic changes are occurring in the brain. Yet, the neurobiological pathways through which socioeconomic status (SES) shapes development remain poorly understood. Behavioral evidence suggests that, relative to other neurocognitive systems, language development exhibits particularly large differences across SES. This may be understood through a theoretical model linking SES differences in linguistic exposure to brain and behavioral development. Specifically, socioeconomic disparities in the quantity and quality of linguistic stimulation in the home have been well described, with higher SES families more likely to speak to children with greater frequency and complexity; spend more hours in parent-child reading activities; and provide increased access to books and other language-related resources. These differences in linguistic exposure have in turn been directly related to child language development. Further, research suggests that differences in linguistic exposure may be associated with developmental differences in language-supporting cortical regions in the left hemisphere. Taken together, the above evidence suggests that socioeconomic disparities, which are associated with large differences in access to language-promoting resources, are likely to be associated with differences in the development brain regions which support the development of language. Here evidence is reviewed from several studies using various modalities (EEG, structural/functional MRI) suggesting that socioeconomic disparities exist in structure and function of regions of the brain that support language processing. It is proposed that these neural differences in structure and function may mediate previously described SES disparities in children’s language skills. Further, effects of experiential differences in language exposure on brain structures may snowball over time, with cumulative consequences for later academic outcomes.