By age 3, the extraordinarily rapid growth of core brain architecture begins to slow, but preschoolers continue to learn and change rapidly, building upon the foundations laid in infancy and toddlerhood. High-quality learning experiences are no less crucial at this developmental stage than in the preceding three years. Preschool-age children require activities and interactions with parents and caregivers that stimulate their growing grasp of language, rhyme and wordplay, numeracy and problem-solving skills.
Children at this age are also primed to develop more advanced behavioral skills that enable them to interact appropriately with others, plan, focus on and carry out tasks, adapt to changes in their environment and control their impulses. All of these competencies directly inform a child's preparedness to enter the K-12 system ready to learn and motivated to achieve.
The achievement gap—the disparity in academic performance between different groups of children—is typically thought to apply only to the K-12 system. However, research into children's early development indicates that this gap is evident well before children arrive at their first day of kindergarten. Children who have inadequate early learning experiences are prone to fall behind their peers in cognition, language, behavioral control and other crucial skills they will need to thrive as they grow. Although this gap is narrow at first, it widens rapidly as developmental disadvantages compound during the preschool years, causing children to lose ground while their peers advance and prepare to enter school.
A child's brain learns rapidly and easily in the first few years of life, physically changing in response to their interactions and environments. But around the beginning of the preschool years, that neural flexibility begins to decrease and the ease with which new synaptic connections in the brain are formed and reinforced declines rapidly.
Thereafter, it becomes increasingly harder to go back and correct problems in core brain circuitry by "overwriting" those earlier neural patterns. Healthy brains never stop learning even in the later stages of life, but the best opportunity to lay the strongest foundations for lifelong growth of cognition and character occurs only in the earliest years.
Early language acquisition is widely recognized by developmental scientists as a predictor of children's likelihood to thrive in the classroom and beyond. This fundamental skill is shaped by the quantity and type of verbal interactions children have with their parents beginning in the first days of life. The more words children hear and the more often they are verbally encouraged by their parents, the more likely they are to develop language skills appropriate to their age.
However, a groundbreaking study of cumulative vocabulary growth in young children (Hart & Risley, 1995) found that gaps appear as early as age 18 months between children from different socio-economic backgrounds. Around age 3, these gaps begin to widen rapidly as children at risk fall further behind. By the time these children arrive at kindergarten, the achievement gap is already well established and growing, making it increasingly difficult for educators and parents to help children keep pace with their peers academically.