Both genetic guidance and experiential exposure are important and play a crucial role in brain development. In fact, the purpose of synaptic overproduction is in part to capture and incorporate experience into the developing synaptic architecture of the brain. Exposure is particularly important during “critical” and “sensitive” periods of development. Critical periods are times during which a set of signals must be present for neural systems to differentiate normally. For example, exposure to patterned visual information in the first few years of life is crucial for stereoscopic vision to develop. Sensitive developmental periods are times when opportunity exists for experience to define patterns of synaptic connectivity, optimizing a child’s ability to adapt to specific environmental factors. Brain plasticity however decreases with age, and as the maturing brain becomes more specialized it is less capable of adapting to new or unexpected challenges. This makes early childhood an important sensitive period in a child’s life, during which experiences directly mold neuronal circuits, offering a critical window for learning [6–9].
Pediatric providers have the unique opportunity to intervene at a time in which the brain is absorbing information at an incredible pace. When children miss the chance to acquire foundational language skills at a very young age, they in turn are at risk for immediate struggles with literacy when they begin attending school. Therefore, for an intervention to have a significant impact on the development of early literacy skills, it has to start early. In the ROR model, pediatric providers start providing anticipatory guidance about the benefits of shared reading, talking, singing, and rhyming starting soon after birth.
Impact of the “Word Gap”
The term “word gap” was first coined by psychologists Betty Hart and Todd Risley in their 1995 book, Meaningful Differences in the Everyday Lives of Young American Children [10]. Their study included 42 healthy and intact young families: 13 high-income families (professional families), 23 families of middle/low socioeconomic status (working-class families), and 6 families who received welfare benefits. Monthly hour-long recordings of parent-child conversations and observations of each family were conducted from the time their index child was about 12 months old until they turned 3 years of age. Gender and race were balanced within the sample.
This study identified remarkable differences in the early vocabulary experiences of young children. The average child raised in a family receiving welfare was hearing half as many words per hour (616 words per hour) as was the average child in working-class family (1251 words per hour) and less than one-third as many than the average child raised in a professional family (2153 words per hour). By extrapolating these numbers in a linear fashion, their study found that the average child growing up in a family living in poverty would listen to about 13 million fewer words than the average child being raised by working class parents and 30 million fewer words than children living in higher income/professional families by the time they reached the age of 3.
To investigate if these findings had longer-term implications, 29 of the 42 families included in their initial study were recruited for follow-up when the children were in third grade. Researchers found that measures of accomplishment at age 3 were highly predictive of performance at the ages of 9 and 10 on several standardized vocabulary, language development, and reading comprehension measures. Thus, the foundation built at age 3 had a great bearing on their progress many years later [11]. This is important because it confirmed that vocabulary development during the toddler and preschool years is directly related to later reading skills and school success in general.