Researchers determine that both nature and nurture develop brains ready for reading

The debate about whether nature (the natural characteristics and temperament which each child is born with) or nurture (whether children can be supported and tended to in order to grow their skills and aptitude) matters more in many aspects of early childhood development is one which has raged for years. 

When it comes to the role of nature versus nurture in developing reading skills, however, cognitive neuroscientists have a clear message – it’s both. 

In new research, presented on Monday at a virtual Cognitive Neuroscience Society (CNS) meeting, scientists reported on biological and environmental factors – including early screen time – and the recent discovery of biomarkers that can identify children at risk for dyslexia and other reading acquisition disorders.

From the earliest days of life, children have neural scaffolding in place, and it is this scaffolding which supports the environmental factors that refine and build reading skills. 

Dr Tzipi Horowitz-Kraus, who chaired the recent meeting, said that reading is a “relatively new human invention”. 

To read, she said, our brains have to ‘recycle’ neural circuits originally used for other abilities such as visual and language processing, as well as attention and cognitive abilities. The presence of dyslexia and other reading challenges in children the world over suggests that there is a biological component to the problem. 

The research put forward by the neuroscience community, as presented at Monday’s meeting, suggests that there are “a variety of biological precursors are present in children prior to school age across languages, and several environmental factors can help or hinder reading acquisition.”

The reading brain in infancy

One of the biggest insights to come in recent years in the study of reading acquisition is that most interventions to identify and treat dyslexia in school were coming too late. Over the past decade, longitudinal studies of young children coming out of the lab of Nadine Gaab at Harvard Medical School and others at labs globally have shown that the brains of children who will develop dyslexia are already atypical even before they start into kindergarten.

Explaining her research and its role in determining the best course of action moving forward, Ms Gaab said “We knew that the brain of someone with dyslexia was different from a control, but we didn’t know if it was something that developed before the onset of formal reading instruction or if it developed in response to a daily failure to learn to read over a significant period of time.” 

Ms Gaab said the work of her team was the first to use MRI imaging to show that some of the brain characteristics predate the onset of reading development. In new work, which was presented at the CNS meeting, Ms Gaab’s team has shown that as a group, babies as young as three months old have an underlying infrastructure that helps predict success in reading years later.

The reading brain on screen

Dr Horowitz-Kraus is now seeking to understand how day-to-day conditions affect the neurobiological foundation for reading in the brain. 

“Although dyslexia is a genetic disorder, the environment has an impact wherein it can reduce or increase reading challenges,” she said.

“The brain is extremely plastic at the pre-reading age, and hence negative stimuli, such as exposure to screens, may have an amplifying effect on a child’s outcomes.”

In a series of studies, Dr Horowitz-Kraus and colleagues examined how the home literacy environment, including screen exposure, affects the brain circuits of children aged between three and five years old, in particular executive functions, language and visual processing. 

Earlier work using EEG had found reduced narrative comprehension in preschool children using screens compared to in-person reading. Researchers had also found that screen exposure engages different brain networks in children with dyslexia compared to typical readers.

The results suggest, Dr Horowitz-Kraus said, that listening to stories through screens is not similar to joint reading when seeking to nurture the developing brain. 

“There is no replacement for joint storytelling in engaging neuronal circuits related to future reading,” she says.

Such studies enabled by modern neuroimaging data are allowing researchers for the first time to determine what infrastructure is needed to be able to read and to track the typical and atypical development of this infrastructure – and to develop appropriate early interventions.

Both Dr Horowitz-Karus and Ms Gaab envision moving to a more preventative model for reading disorders. 

“This preventive model is something we embrace a lot in medicine but for some reason, we have not yet done so in education,” Ms Gaab said, citing cholesterol screening to help identify those at risk for heart disease as a model that could work for dyslexia and other learning disorders.

The symposium, Moving from a Deficit-Oriented to a Preventive Model in Education: Examining Neural Correlates for Reading Development, took place at CNS 2020 Virtual, held 2-5 May.