Early Childhood Experiences Shape The Brain’s Physical Architecture

This is the first in a series of articles the RoundTable will publish on early childhood experiences, childcare and early education. This article focuses on the importance of early childhood experiences in forming the architecture of the brain, and primarily relies on three recent reports:  “The Science of Early Childhood Development,” Jan. 2007,  prepared by the National Scientific Council on the Developing Child (“NSCDC”) (the “2007 Report”); “A Science-Based Framework for Early Childhood Policy,” Aug. 2007, prepared by the NSCDC and the National Forum on Early Childhood Program Evaluation (“NFECPE”) (the “Joint Report”); and “The Timing and Quality of Early Experiences Combining to Shape Brain Architecture,” Feb. 2008, prepared by NSCDC (the “2008 Report”). Both NSCDC and NFECPE are based at the Center on the Developing Child at HarvardUniversity.

Continuing research in neurobiology is clarifying the extent to which the interaction between genetics and early childhood experiences physically shape the architecture of a child’s brain.

The debate about whether a child’s brain is shaped by genes or by experience is over. “It’s both. And the truth is in the interaction,” said neuroscientist Judy Cameron, a member of the National Scientific Council on the Developing Child (NSCDC), in the perspective “Stress, Neural Systems, and Genetic Code.” (2006)

These early experiences – whether nurturing toward positive growth or stressful to the point of being toxic – have “an enormous impact” on how the brain’s lower-level neural networks are connected or “wired” together and become the building blocks for more advanced circuits. Thus, “early experiences determine whether a child’s developing brain architecture provides a strong or weak foundation for all future learning, behavior, and health,” say the NSCDC and the National Forum on Early Childhood Program Evaluation (NRECPE) in their Joint Report.

While brain circuits shaped through early experiences retain “plasticity” and “may adapt their architecture, at least partially, to experience in adulthood,” later interventions are less effective, less efficient and more expensive “than getting things right the first time,” says NSCDC. (2008 Report)

Scientists and researchers are thus putting increased emphasis on the need to ensure that all children have positive early childhood experiences. The NSCDC says in strong terms: “The need to address significant inequalities in opportunity, beginning in the earliest years of life, is both a fundamental moral responsibility and a critical investment in our nation’s social and economic future.” (2007 Report)

Shaping the Brain

Current research shows the brain is physically shaped by the interaction among genes, the environment and experience. The NSCDC says, “The brain is composed of billions of highly integrated sets of neural circuits (i.e., connections among brain cells) that are ‘wired’ under the interactive influences of genetics, environment and experience.” (2007 Report)

 Genes provide the “initial plan for the brain’s architecture,” says NSCDC. It is like the “blueprint for a house” provided by an architect. (2008 Report)

The environment in which the brain develops, beginning in the prenatal period, “can have a profound influence on its architecture,” says the NSCDC. After birth, experience – or the interaction of a child with his or her environment  – “plays an increasingly important role in shaping the architecture of developing neural circuits so that they can function optimally for each individual.” (2008 Report)

Just as an architect’s plan for a house is shaped by the selection of high or low quality materials and shaped by the contractor in building the house and making adjustments as the job progresses, the brain’s architecture is also shaped by nutrients, exposure to toxins, and interactions with adults and other experiences, says NSCDC. (2008 Report)

Early Experiences Have
     Far-reaching Effects

Brain development has “sensitive periods”  – periods in which certain neural circuits are very receptive and grow dramatically. The sensitive periods for neural circuits that perform low-level analyses of sensory stimuli tend to end before or soon after birth, says NSCDC. The sensitive period for high-level circuits ends much later in development.

  “Early environments and experiences have an exceptionally strong influence on brain architecture,” says NSCDC. As a neural circuit is maturing and beginning to function, a child’s environment and experiences “can have an enormous impact on that circuit, causing adjustments in its genetic plan and changing its architecture in fundamental ways.” (2008 Report)

These critical sensitive periods are “double-edged swords,” says NSCDC. “On the one hand, a sensitive period enables a neural circuit to optimize its architecture for the needs and environment of the individual. On the other hand, this period of extreme receptivity also makes the circuit vulnerable to the damaging effects of adversity.” (2008 Report)

The importance of developing healthy brain architecture at the earliest stages is heightened by findings that the brain’s architecture is built “from the bottom up.” Lower-level neural circuits that are developed through very early experiences, provide the foundation for more advanced neural circuits. If the lower-level circuits are not wired properly, it becomes more difficult to build the higher-level circuits, according to NSCDC. (2008 Report)

Just as a faulty foundation has far-reaching detrimental effects on the strength and quality of a house, adverse early experience can have far-reaching effects on the development of brain architecture,” says NSCDC. (2008 Report)

 “Once established, a weak foundation can have detrimental effects on further brain development, even if a healthy environment is restored at a later age.” (2008 Report)

Healthy Influences

Research shows that an environment that is nurturing, responsive and language-rich fosters healthy development. This can be found in the home, in a childcare center, or even a casual local program. Responsive interaction with a child is critical.

 NSCDC says, “When parents, informal community programs, and professionally staffed early childhood services pay attention to young children’s emotional and social needs, as well as to their mastery of literacy and cognitive skills, they have maximum impact on the development of sturdy brain architecture and preparation for success in school.” (2007 Report)

The advantage of reading to a young child and using more cognitive language in a household shows up early in children. A recent study found that mothers who read to their children at ages one and two had children with significantly elevated language and cognitive skills. NSCDC, Science Briefs: The Effects of Early Reading with Parents on Developing Literacy Skills (2007).

In addition, research shows that “young children who grow up in homes with high incomes and high parent education levels have more than twice the expressive vocabulary at age three compared to children raised in homes characterized by low socioeconomic status,” says NSCDC. (2007 Report)

While a language-rich, responsive home promotes healthy development, NSCDC cautions against pushing too fast. “When adults or communities expect young children to master skills for which the necessary brain circuits have not yet been formed, they waste time and resources, and may even impair healthy brain development by inducing excessive stress in the child,” says NSCDC. (2008 Report)

And while there is “well-documented scientific evidence of the negative impacts of deprivation on brain circuitry,” NSCDC states the converse may not hold: This finding “does not mean that excessive enrichment produces measurable enhancement in brain architecture.” (2008 Report)

 “For the vast majority of kids in normal homes, all they will need in order to develop strong brain architecture is the kind of rich experience they will get from everyday interactions,” said developmental psychologist William Greenough, a member of the NSCDC, in the perspective “Rich Experiences, Physical Activity Create Healthy Brains.” (2006) “But if the parents don’t provide this experience, the children can’t make up for it on their own.” 

Negative Influences

Adverse early experiences can have far-reaching detrimental effects on the developing architecture of a child’s brain and provide a weak foundation for all future learning, behavior and health, according to NSCDC. (2008 Report)

A child who lacks critical nutrients, or who is exposed to toxins, such as alcohol, cocaine or lead, can suffer adverse effects. “These effects or threatening environmental conditions can cause neural circuits to change in ways that prevent them from functioning well, or at all, even in a subsequent healthy environment,” says NSCDC. (2008 Report)

In addition, toxic stressors, such as recurrent child abuse or neglect, severe maternal depression, parental substance abuse, or family violence, “can have adverse effects on developing brain architecture, which weakens the foundation upon which future learning, behavior, and health are built,” say the NSCDC and NFECPE. (Joint Report) These stressors “can lead to difficulties in learning and memory, as well as health-damaging behaviors and later adult lifestyles that can undermine well-being over time.” (Ibid.)

Inadequate stimulation or barriers to opportunity for productive learning can also lead to early disparities in capability that generally persist in the absence of effective intervention, according to NSCDC. “Consequently, children who live in families with lower income and less parent education begin to score lower on standardized developmental tests as early as 18 months, and the differences typically increase into the school-age years,” says NSCDC. By age three, their expressive vocabulary is one-half that of children who grow up in homes with high incomes and high parent education, says NSCDC. (2007 Report)

Policy Implications

In light of the increased understanding of the extent to which early childhood experiences shape brain architecture, the NSCDC says, “it is vitally important to take advantage of these early opportunities in the developmental building process.” (2008 Report) A continuing theme of the NSCDC is, “It is more effective and more efficient to get things right the first time than to try to fix them later.” (2008 Report)

Some of the NSCDC’s suggestions include:

• Improve health and nutrition. “Given the multitude of preventable threats to brain architecture early in life, high-quality health care and adequate nutrition before birth (for pregnant women) and after birth (for both the primary caregiver and baby) are fundamental to the promotion of healthy child development.” (Joint Report).
• Increase the availability of research-based programs that begin immediately after birth (and preferably prenatally), to enhance the experiences of young children in families with limited education and low income. “Effective programs provide center-based, growth-promoting experiences for the children, as well as help their parents create a home environment that provides the kind of positive social interactions, rich language exposure, and early literacy experiences that increase the probability that their child will enter school with the social, emotional, and cognitive skills needed to succeed.” (2008 Report)
• Enroll all children who meet eligibility criteria in early intervention programs as early as possible. This would require the need to identify sensory and cognitive impairments as soon after birth as possible. “When compensatory adjustments are facilitated as early as possible, they help build a sturdier foundation for later achievement of higher-level skills,” says NSCDC. (Ibid.)
• Provide developmental assessments and intervention services for young children experiencing significant adversity (i.e., those exposed to child abuse, serious neglect, prolonged or repeated exposure to violence) before they exhibit problems in their behavior or development. “This will increase their chances for more positive life outcomes,” says NSCDC. (Ibid.) 

The Joint Report says successful programs have generated benefit-cost ratios ranging from 2:1 to 17:1 depending on the program. (Joint Report)  The report cautions, however, “Programs that cost less because they employ less-skilled staff are a waste of money if they do not have the expertise needed to produce measurable results.” Ibid. In addition, interventions “that are poorly planned or implemented have generated few to no beneficial effect.” (Ibid.)

January 7, 2009