What Science Is Telling Us

How Neurobiology and Developmental Psychology are Changing the Way Policymakers and Communities Think About the Developing Child

In a nutshell, it comes down to the fact that a child’s “environment of relationships matters critically,” says Gunnar. “Consistent relationships with caring adults are essential for healthy development. Providing these loving relationships can do a lot to help kids get back on track after they’ve been seriously neglected early in life.”

The Importance of a Stimulating Environment

Exploring and interacting with people and things—and getting feedback from a challenging and stimulating environment—are key to building a solid brain structure, experts say. Even in something as simple as a game of “peek-a-boo” or silly word play, children are exercising their innate curiosity and, ideally, getting positive reinforcement from the adults around them, who “mirror” their patterns of facial expressions, coos, and gestures. Among the many significant things research now tells us about child development is this: The old construct of “nature” versus “nurture” is much too simplistic and the debate over which is more important is scientifically obsolete. Instead, scientists have shifted their focus to reflect the fact that genetic and environmental influences work together in dynamic ways to shape the architecture of the child’s developing brain. At any time, both are sources of tremendous growth and potential—as well as serious risk. Anyone who has raised a child understands this balance in one form or another.

Many of the Council members study this balance in their own research. For example, Eric Knudsen considers the effects of early experience on the structure and function of the brain—using the central auditory system as a guide. Knudsen, a neurobiologist at Stanford University’s School of Medicine, says the science demonstrates “how experience early in life is particularly important in learning how to understand auditory stimuli and shape pathways in the brain, effects that last a lifetime.” Some of these pathways—those that control breathing or our knee-jerk reflex, for example—are genetically programmed very tightly from birth, while others—those involved in higher-order processes like memory, cognition and emotion, for instance—are shaped profoundly by environment and experience, he explains. The interaction of genetic and experiential influences on the brain is at the heart of his work.

The complex ways in which genetics and environment interact as the human child develops also compel the research of Pat Levitt. By focusing on the origins of schizophrenia and seizures, for example, his team seeks to understand why certain genes seem more susceptible to problems and how environmental factors can influence that vulnerability. “Our nervous system comes partially assembled, but most of it—all the fine-tuning—really comes about through interactions with the environment,” he explains, echoing other Council members.

The Importance of Social and Emotional Growth to Brain Architecture

Most parents recognize the relation between a child’s mood and attitude and the quality of his or her interactions and learning. What they may not know is how that happy-go-lucky or painfully shy character is formed in the early years, and how it depends on features of brain architecture that change through experience.

Nathan Fox, a developmental psychologist at the University of Maryland, studies the role of an infant’s temperament in the development of social competence. “What makes up the temperamental differences in babies from the get-go?” he asks. “Why do some respond to sound by startling easily while others could sleep through a Marine Corps marching band? Why are some highly sensitive to touch while others are more physically playful?” By exploring these questions, Fox’s research looks at the keys to healthy personality development—and, conversely, “why some children set off on developmental trajectories that are not very adaptive, like impulsivity or aggression.”

How healthy personalities arise also concerns Council member Ross Thompson. This University of California-Davis developmental psychologist studies early relationships and their importance to social, emotional, and personality development in children. Specifically, his research investigates “ways in which the most simple conversations between young children and their parents lay a foundation for conscience development, emotional understanding, and, we think, a sense of self” early in life.

Special Developmental Challenges for Poor Children

To be sure, knowledge about early childhood trajectories is a good thing. The more we know, the better prepared we are to act in the best interests of the next generation, so that all children get off to a good start in life. But sometimes that knowledge raises troubling concerns—as in the case of evidence about the hurdles facing poor children. Deborah Phillips, a Georgetown University psychologist, puts it starkly: “By the age of two, striking differences in what children know and can do begin to distinguish low-income children from their better-off peers.”

Science shows that differences in standardized test scores begin to emerge as early as 18 months. On average, poor kids at 5-6 years of age understand numbers as well as middle income 3-4 year olds. These differences in development and achievement result in large part from “early environments at home and in child care that don’t constitute a level playing field,” explains Phillips. For example, children living in poverty hear, on average, 300 fewer words per hour than children whose parents are professionals. That disparity has lasting consequences, as it predicts later differences in vocabulary and reading comprehension. Importantly, it also affects children’s conceptual development—what they know about the world around them—which plays a central role in school achievement, says Phillips.

Differences like these surely don’t reflect a lack of love or commitment on the part of low-income parents. Sadly, though, the environments in which many disadvantaged kids are raised may simply not be rich enough to support their full development. Their parents may be working multiple jobs, or are not as available or as verbal as the child needs. Too often, the child care that’s affordable is of very poor quality and results in a warehousing situation, not a stimulating environment. As Nathan Fox observes, young children need “sturdy scaffolding” to optimize their skills. “What middle-class parents do a lot of is provide this scaffolding,” he says. But due to a range of circumstances, “lower-income parents may not have the opportunity to provide that kind of support.”