Tracing the Roots of Language and Literacy

Researchers have long known that a child’s brain develops the capacity for language rapidly and as a response to environmental input like listening to a story, talking with a caregiver, or looking at pages in a book. Up until now, though, the relationship between brain structure — specifically the organization of white matter, or the way the bundles of messaging tissue, or axons, connect different parts of the brain — and language and reading was only observed after the onset of formal schooling. But a new study establishes that the influence of the organization of white matter on subsequent language and literacy skills may be observed as early as infancy.

The study, coauthored by Harvard Graduate School of Education Associate Professor Nadine Gaab; Jennifer Zuk, Ed.M.'10; Joseph Sanfilippo, Ed.M.'16; HGSE postdoctoral candidate Theodore Turesky; and researchers at Boston Children’s Hospital provides evidence that structural brain networks in infants as early as four months after birth are linked to later language and reading skills. The study, published in Developmental Cognitive Neuroscience, presents some of the first evidence of these early, structural networks and their relationship with long-term language and literacy development.

Brain Organization in the First Year of Life

Although white matter develops and changes so rapidly over the first two years of a child’s life, the relationship between white matter organization in infancy and subsequent language and literacy skills in kindergarten had yet to be studied at this early age. “We’ve known for a long time that language skills are related to a child’s brain development and are shaped by the environment,” Gaab says. “What we didn’t know was how early this relationship can be seen, if the development depends entirely on the environment, or if ongoing experience builds on foundational white matter organization throughout development.”

>> Read the full study in Developmental Cognitive Neuroscience

To determine whether white matter in infancy relates to language and literacy development later in life, the researchers used MRI technology to generate images of white matter pathways in 40 infants and then, five to six years later, used a variety of language and literacy assessments to track each child’s development. Gaab and her coauthors focused their study specifically on one white matter pathway called the arcuate fasciculus, which is linked to language and reading development in older children and adults. 

After controlling for external factors that may have an impact on language and literacy development, such as parents’ education levels and socioeconomic status, the findings link white matter organization in the arcuate fasciculus in infancy with subsequent oral language and pre-literacy abilities like phonological awareness and vocabulary knowledge.

According to Zuk, the paper’s first author, this is the first study to demonstrate that the white matter present within the first year of life does continue to impact language and literacy as children grow. As such, they deepen the field’s current understanding of how the brain learns to process language.  

The Capacity for Language and Literacy

The existence of this early foundation does not discount the strong influence of environmental factors, for example, engaging children in language-rich conversations or reading to children. And caregivers need to provide children with these important experiences to promote language and literacy development. According to Gaab, the link between white matter organization in infancy and subsequent literacy “does not mean that our brain is set in stone when we are born.” But, at the same time, these findings highlight the importance of the first year of life in setting children up for success later in life.