A child’s brain experiences a growth spurt during the preschool years as they learn new skills and are exposed to new stimuli. Not only does the brain increase in complexity but it also increases in size. At 3 years old, a child’s brain is about 80% of its adult size and by 5 years of age it will be around 90%. Brain research tells us that “the preschool years can be thought of as a developmental period generally dominated by dynamic and robust progressive processes, with an emphasis on growth, expansion, “construction”, and “blossoming” that will later be pruned and tuned with continued maturation and experience” (Brown & Jernigan, 2012).

One of the most dramatic changes that happens during the preschool years is growth within the prefrontal cortex. The prefrontal cortex is an area of the brain, located at our foreheads, which is responsible for a number of important skills. The brain also experiences improvement in other areas such as the corpus callosum, which is a structure that connects the two hemispheres of the brain. This growth results in improved coordination between the two sides which helps perform complex functions (Tanaka-Arakawa et al., 2015). We can witness this change when preschoolers become more physically coordinated and through improvements in cognitive thinking skills.

Preschool aged children experience a peak in executive functions and will continue to develop these into early adulthood (Center on the Developing Child, 2023). Executive functions are thought processes that include working memory, attention, problem solving, and impulse control. These prefrontal cortex functions are crucial in helping children complete tasks, plan and make decisions, as well as control their behavior. Caregivers are a child’s first teacher and they actively teach children how to manage themselves through modeling and practicing skills. Self-regulation skills are strategies that are used to manage thoughts, behaviors, and feelings. They are key in the development of healthy executive functions.

Responsive caregivers who give their children attention and help them sustain attention through positive interactions are providing a framework for executive functioning in the early years. Self-regulating skills take much practice and time to master but preschool aged children can build self-regulating behaviors when given ample opportunities by their caregivers. Caregivers should ensure that children have plenty of time to play, that there are established routines at home and that they scaffold learning for their children, especially when encountering something new.

Children who do not have the opportunity to practice important brain skills or who experience disruptions in the preschool years can develop delays in their learning or social functioning. For example, a child living in extreme poverty may not have access to adequate nutrition to support the developing brain. This can lead to delayed growth or impairment. Similarly, adverse experiences such as exposure to violence and abuse create stress within the developing child. This type of toxic stress can “disrupt brain architecture and impair the development of executive functions” (Center on the Developing Child, 2023).

In Chapter 5 we learned that young children’s brains are highly plastic which allows them to adapt to environmental factors and new experiences. Not all adaptations are necessarily good for the developing child. While plasticity is an important brain process that prepares children for their environments, it can also lead to changes within the brain that impact memory and other important cognitive functions. For example, the brain of a child exposed to constant threats in their lives will rewire itself for faster activation of fight, flight or freeze responses. This can lead to increased anxiety, depression and stress in later childhood and adulthood (Herzog & Schmahl, 2018).

The use of screen based media continues to be a factor to consider in brain development. We learned that infants and toddlers are spending more time in front of screens via television, phones, and i-pad computers. A report shows that preschoolers spend a daily average of 2.5 hours to just over 3 hours on a screen of some kind (Rideout & Robb, 2020). While screen time on its own isn’t necessarily going to damage the brain, it is important to consider the cumulative impact of screen use from infancy through the preschool years. Children who experience delays early on may experience even more delays in later development.

When children are in front of a screen, especially without parental engagement, they are missing out on important interactions that help strengthen vital brain connections. Preschoolers are becoming increasingly independent but continue to need positive support from the adults in their lives. Most importantly, meaningful child-adult interactions, such as reading or playing together, are key to supporting healthy brain growth.