In a recent study, the Gaab Lab examined how family literacy practices play a role. The researchers looked at the brain activation of 50 soon-to-be kindergartners during a phonological processing task — where the kids were asked to think about whether certain words started with the same sound (for instance, “goat” and “gorilla,” or “bird” and “ant.”). Twenty-nine of the children had a familial risk of dyslexia and 21 did not; none had begun reading yet.
Gaab and her team looked at these neuroimaging scans alongside descriptions of each child’s home literacy environment. Parents reported the number of books in their homes; how often and for how long they read to their child; how often they discussed the alphabet; and how often the child looked at books by his or herself. The researchers controlled for each family’s socioeconomic status and parent education level.
Crossing the Neural Divide
The networks that govern our phonological processing skills, which are necessary for reading, usually exist primarily in the left side of our brains, and the researchers saw activation in that area for the children without a familial risk of dyslexia. But children with a sibling or parent with dyslexia and strong home literacy practices also activated the right side of their brains (specifically, the right precentral gyrus) to think about words and sounds.
It’s unclear why this shift occurs — whether the right-side reading network is innate, or whether family reading practices help create it. The Gaab Lab has collected data showing that children with a reading network in the right hemisphere also have a stronger corpus collosum, which is the white matter that connects the two cerebral hemispheres. “It may be that part of the reason why we’re seeing this activation is that starting from birth these children are less ‘lateralized,’ meaning they’re in general processing information more in both hemispheres,” says Gaab, who is a faculty member at the Harvard Graduate School of Education and Harvard Medical School.
But family practices likely play a role as well. Gaab also theorizes that children who are born susceptible to dyslexia have atypical brain development in the left hemisphere, which makes it difficult for them to develop components of the language and reading network there. But neural networks are incredibly malleable. She thinks that strong environmental factors, such as listening to parents read, singing the alphabet together, and making connections between stories, may enable a detour of the reading network across the corpus collosum to the right side of the brain, in order to make up for that genetic influence.