Skip to main content
Social Sci LibreTexts

2.2: What We Know About the Brain

  • Page ID
    200781
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    A child sits facing forward holding books.
    Children enjoy books © Unsplash is licensed under a CC0 (Creative Commons Zero) license

    There is little argument that brain science has elevated the discussion about the importance of development from birth to age five (National Scientific Council on the Developing Child, 2007; IOM & NRC, 2015). These years are fundamental in brain growth in a way that is unique from other time periods. What we do in these years matters–the risks are more pronounced and the opportunities for enrichment more impactful. Babies’ brains are roughly one quarter the size of an adult brain; however, at birth a baby has 100 billion neurons (UNICEF ECARO & ISSA, 2016). Neurons are cells designed to carry messages from one part of the brain to another part. All of these billions of neurons are present in the brain at birth, but most are not connected. The brain continues to develop throughout the lifespan; however, more than a million neural connections, or synapses, are made each second in the first few years of life (Center on the Developing Child, 2007). Graham & Forstadt (2011) explain,

    Each individual neuron may be connected to as many as 15,000 other neurons, forming a network of neural pathways that is immensely complex. This elaborate network is sometimes referred to as the brain’s ‘wiring’ or ‘circuitry.’ As the neurons mature, more and more synapses are made. At birth, the number of synapses per neuron is 2,500, but by age two or three, it’s about 15,000 synapses per neuron. This is like going from 100 to 600 friends on Facebook, and each of those friends in turn, is connected to 600 more people! The neural network expands exponentially.

    Because of the extensive neural connections during early childhood (see Figure 2.1 below), this age range is considered one of the “sensitive periods” when the brain is naturally geared toward learning. Brain researchers tell us that the brain is more malleable or has more “plasticity” in early childhood. This means that during the first few years of childhood the brain is more susceptible, and this susceptibility can have two inverse impacts. Ideally, early experiences prepare young children for the future by establishing capabilities when development is most responsive to stimulation. However, it is also possible that in a less-than-ideal setting, the young child is more vulnerable to the absence of these essential experiences, resulting in the risk of future brain dysfunction (National Research Council & Institute of Medicine, 2000).

    Essentially, the simple circuits built during early childhood enable complex circuits to more easily make the initial pathways (Center on the Developing Child, 2007). These pathways work to create literacy in that verbally labeling an object depends upon the earlier ability to differentiate and produce the sounds required for that word in the child’s language. The ability to verbally label an object then leads to the skill of grouping words into phrases and using this language to read or write words and phrases. If these circuits are used repeatedly, they become more efficient, but those not used fade away or are “pruned.”

    This video provides a vivid picture of brain development in young children.

    After viewing the video, summarize the main points in your own words.

    The neural connections in the brain develop rapidly from birth to 2 years when they are strengthened by use or pruned when they are not used.
    Figure 2.1 Neural Connections in Early Childhood. Postnatal development © Bryanna Adams and Kalyca Schultz is licensed under a CC BY-SA (Attribution ShareAlike) license

    There are many ways that brain architecture is impacted during the birth-to-five window. The development and strengthening of circuits form the foundation of, among other things, emotional regulation, motor control, cognition, language development, and more. Figure 2.2 shows three different brain functions that develop sequentially. You will notice that all three functions expand significantly in the first five years and are directly connected to children’s literacy development. The first, sensory pathways, are essential for initial communication and support the development of language. We will spend an entire chapter in this textbook (see Chapter 7) on language, the second function. Language plays a critical role in building foundational literacy competencies and develops in distinct but overlapping stages; however, the quality of language that children hear impacts development. The last function displayed in Figure 2.2 is cognition. This includes memory, sustained attention, mental flexibility, and the ability to make a plan, among other skills. Researchers also know that gross motor skills, such as crawling, walking, and balance, are predictive of cognitive function and impacted by brain development. It is clear from the brain research that these functions are critical for overall development and impact children’s literacy foundation.

    The line at the bottom of the graph labeled human brain development by age reads from left to right, conception, birth, one year old, and 18 years old. Three bell curves are shown. Sensory pathway begins after conception, peaks before birth, and ends after one year old. Language pathway begins after conception, peaks between birth and one year old, and ends after one year old. Cognitive pathway begins after conception, peaks around one year old, and continues to 18 years old.
    Figure 2.2 Human Brain Development by Age. Brain development by age © Dale Dulaney and Kalyca Schultz is licensed under a CC BY-SA (Attribution ShareAlike) license

    Another function of the brain not shown in the figure is social competence. Research has shown that children’s ability to identify and express emotions, cope with strong feelings, engage in self-regulation, and develop empathy in early childhood are all key markers to forming successful relationships later in life and becoming a productive member of society (Levitt & Eagleson, 2018; National Scientific Council on the Developing Child, 2004). A number of studies have shown that children who have acquired these skills by kindergarten have an increased rate of graduating from high school, attending and completing college, and finding and maintaining employment in adulthood (Jones, Greenberg, & Crowley, 2015).

    Children helping to push a red wagon
    Children develop social skills as they interact with teachers in many settings such as exploring the outdoors. Children in nature © Flickr is licensed under a CC0 (Creative Commons Zero) license

    This research also showed an inverse relationship between low levels of social skills and increased predictability of substance abuse behavior, involvement in the justice system (e.g., being arrested), and needing public assistance. It is clear that supporting children’s emotional foundation by the end of preschool is vitally important. An emotional foundation is essential for social competence and impacts children’s school success.

    Brain development is impacted by many factors including genes, relationships, environments, and experiences. The quality of the environment and experiences impacts how genes are expressed and how the brain architecture is structured. These elements are also often tied to the type of relationships that children establish with adults and collectively build the foundation of the brain’s structure. The figure below (McCain, M., Mustard, J.F. & McCuaig, K., 2011, p. 39) shows how these factors interact with brain development.

    Genes and experiences affect brain development and impact learning, health and behavior.
    Image adapted from McCain, M., Mustard, J.F. & McCuaig, K., 2011, p. 39. Genes and experiences affect brain development and impact learning, health and behavior. Factors Influencing Brain Development © Kalyca Schultz is licensed under a CC BY-SA (Attribution ShareAlike) license

    The brain changes in many amazing ways during the early childhood window, but precisely for this reason, there are also factors that can have a negative impact on development. It is important for early childhood educators to understand the impact that trauma and adversity can have on the developing brain. The vast promise of early brain development is a tremendous opportunity to impact children’s entire school experience as well as future life trajectory. But with this opportunity also comes significant challenges if children are experiencing trauma. Stress creates a physiological response in the body, which is healthy in small doses, but toxic stress from traumatic events negatively impacts brain development. Continually elevated cortisol levels can be toxic for the developing brain and have serious implications for learning and behavior (Center on the Developing Child, 2007). As important as these implications are, it is also critical to know that this is not necessarily the end of the story. The impact of toxic stress can be mitigated by developing resilience through relationships.


    This page titled 2.2: What We Know About the Brain is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Sandra Carrie Garvey (Remixing Open Textbooks with an Equity Lens (ROTEL)) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.