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Science Says

When it comes to growing young minds, it’s better to get it right the first time than to try to fix it later

by Lory Hough

baby with preschool children

During the middle of her interview for this story, Dean Kathleen McCartney gets up to take a call at her desk. A reporter from the Associated Press is on the line and wants to talk about the same subject: early childhood development. It’s a topic McCartney knows well, having studied it for 25 years without much fanfare.

Jack Shonkoff, director of Harvard’s new Center on the Developing Child and a pediatrician by training, is getting his share of calls as well these days — at least two or three a week. And it’s not only the media; policymakers and advocacy groups contact him for briefings and ask him to speak at their events.

Suddenly this subject, relegated for years to academic and family circles, is red hot. And the biggest reason why, says Shonkoff, has nothing to do with politics or celebrity or scandal. It has to do, primarily, with something much less sexy: science.


Science Says

How did this happen? For years people thought that not much was going on when kids were very young, at least when it came to their brains. Today, science tells us the exact opposite: A huge amount is going on, and what is happening in those early months and years of a baby’s life directly affects whether he or she will have a good start or a troublesome one.

“Brains are built over time,” Shonkoff says. They also don’t come fully wired.

“What’s critical then is the interaction between genetics and what we call ‘serve and return’ between young children and the adults in their lives,” Shonkoff says. “The child does something and the adult responds. The adult does something and the child responds. Back and forth, serve and return, like in tennis or volleyball. It’s that back and forth that literally, and I mean literally, shapes the architecture of the brain.”

This back and forth interaction can include babbling, facial expressions, gestures, cries, and words, says Shonkoff, a professor at the Harvard Graduate School of Education and the Harvard School of Public Health.

Brains are also built from the bottom up, in layers, similar to a house. First there’s the foundation, then the rooms are framed, then the electrical system is wired, Shonkoff says. While this is happening, the circuits — the connection between brain cells — are being formed. What science now tells us is that very early in life there are “sensitive periods,” fixed windows of opportunity when certain parts of the brain are being wired for certain skills, such as associating sounds with objects or putting words together. Once that sensitive period passes, the circuit is formed and can’t be rewired.

“As new circuits are being built, if they’re building on earlier circuits that were wired properly, they work really well,” Shonkoff says. “If they’re building on earlier circuits that weren’t wired properly, it’s a harder job for the brain to adjust. There are greater energy demands on the brain. It’s a bigger cost to the brain to try to develop adaptive behavior and adaptive skills by overcoming and getting around faulty circuits.”

So what prevents circuits from being wired properly in young children? Poverty, the lack of free time for parents and other adults to interact with young children, mental health issues, inadequate childcare centers, and other factors often prevent babies from getting the kind of stimulation they need. Persistent negative stress (family chaos, abuse, chronic neglect) is also a major factor, affecting the nervous and stress hormone systems. Shonkoff says the brain can compensate for all of this, but it’s much harder than if the child gets the right kind of nurturing and interactions from the start.

“Whenever you’re developing any skill, you’re never coming at it in a vacuum. The brain inherits what was there before,” he says. “All of the forces of nature are designed for positive adaptation. The brain is wired to do the best it can do with whatever it has to work with. If it has good early circuits, it zooms along. If it has poor early circuits to work with, it has to work harder. In terms of what that looks like for outcomes, the earlier you intervene and get it right, the greater the likelihood of getting the best possible outcome at the least cost. You rarely say it’s too late to intervene, and you’d never say I don’t think a kid can accomplish this or that, but it’s much harder. There’s nothing about development or behavior that’s irreversible, but circuit development certainly is.”

Take reading, for example. If a baby doesn’t hear words or babbling early on, the foundation for learning more complex language skills, like reading, is weak.

“Vocabulary turns out to be very important,” says McCartney. “If you don’t know what words mean, you can’t read them.”

This is why Shonkoff says we need to pay much more attention to the zero to five age range, not only for the sake of babies at risk, but also for the overall health of the country.

“The quality of early experiences, both within the family and the community, really sets the stage for whether there is going to be greater or lesser likelihood for success in school, which is going to affect success in the workplace,” he says. “It’s going to affect the greater or lesser likelihood that you’re going to be healthy or have problems with some of the common diseases that are all stress related, to some extent, like hypertension, diabetes, cardiovascular disease, depression, anxiety disorder, and substance abuse, including alcoholism. All of these have a combination of genetics and experience as triggers. The experience triggers start to have their influence very early in childhood.

“If you want a bumper sticker for this, it would be: It’s better to get it right the first time than to try to fix it later,” he says.


baby in preschool classNew but Not New

We’ve known about a lot of this for decades, Shonkoff says, but it was mostly based on behavioral science, not the neuroscience that’s become prominent today.

“There’s a lot we know about early development and early behavior that we’ve known for decades from developmental behavioral research, but now we’re confirming this through neuro-imaging studies and other kinds of neuroscience and people are taking note,” he says.

One example: About 20 years ago, Children’s Hospital, Boston, did a study with really young babies who lived alone with seriously depressed mothers. After watching the babies for a short period of time, it became clear that their behavior was affected.

“The babies themselves became less inquisitive, their affect became more blunted, they had flatter emotional responses, and became somewhat withdrawn as a result of living with a depressed mother,” Shonkoff says. “Their exploratory behavior was much less than children who were cared for by adults who were more emotionally available. This isn’t to blame depressed mothers. Serious depression is an illness.”

Flash forward two decades. Another study is done between depressed mothers and their babies, this time using an EEG test to detect problems in the electrical activity of the brain. They found the same results — babies of seriously depressed mothers were affected. More specifically, the brain waves of these babies were altered.

“People said, ‘Whoa! This is big news! You mean it’s affecting the baby’s brain?’” Shonkoff says. “The behavioral people said, ‘Of course. We told you that 20 years ago. Look at their behavior.’ Behavior is one thing, but if it’s in the brain, then it has more clout. But of course it’s the same thing. When behavior is different, the brain is different. When brains are operating differently, you’re going to function differently. Advances in neuroscience have taken what we’ve known for a while and made them more concrete in terms of how it actually plays out in the brain. It’s resulted in more attention being given to these things.”


Other Factors

Science may be driving our new interest in early childhood learning, but there are other factors as well, including another unlikely hero: economists.

“Economists have demonstrated that investments in early childhood pay off,” McCartney says. “For every dollar spent, society saves between four and six dollars. Here’s why: Early childhood programs result in lower rates of special education, kids are less likely to be retained in a grade, and they’re more likely to graduate from high school.”

The weight of globalization has also upped the need for a capable, skilled workforce.

“There’s a dramatic transformation of the workplace,” Shonkoff says. “Twenty years ago, if you had just a high school education in this country, or even if you didn’t have a high school diploma but you were willing to work hard and you had a good work ethic, you could get a manufacturing job that would give you enough money to support a family; that’s not true in this country anymore. If you have a high school diploma and nothing else, there aren’t a lot of jobs that will give you any kind of economic security. Those jobs have all been shipped overseas. We’re in a global economy right now.”

This is why the business community, and increasingly people in government, has begun to take more of an interest in raising healthy, capable kids, Shonkoff says.

“It’s an economic survival skill for the country. If you link that to all of this research that shows how much the early roots of learning are established before school starts, it’s another reason to be invested in paying more attention to this,” he says.

The changing nature of families in America is also playing a role in the increased attention to this issue. Families are under much more stress, at all income levels, in terms of balancing family responsibilities and work responsibilities.

“The increased rates of maternal employment that began in the 1980s means that more families are using childcare, often as soon as a child is born,” McCartney says, “which means families are much more interested in having quality programs for their children.”


What Works

“Of one thing I’m certain: Children are born ready to learn,” Kathleen McCartney says. “All cultures need to ensure that children are in stimulating environments, whether they’re at home or in school. When formal schooling starts is a question for each culture to answer for itself.”

So what’s the answer? Do we fund preschool for all kids universally? Do we target the ones who need help the most, from birth? Do we better train parents or pay mothers or fathers to stay home with their children? Or do we create formal schools for newborns, like Australia considered a few years ago?

“Being ready for school is a lot more than formal curricula,” says Gillian Najarian, deputy director of the Center on the Developing Child. “It’s not that early cognitive skills aren’t important, but you also need to have empathy and self control and the ability to socialize and get along with others.”

McCartney says there is no one right answer.

“Of one thing I’m certain: Children are born ready to learn,” she says. “All cultures need to ensure that children are in stimulating environments, whether they’re at home or in school. When formal schooling starts is a question for each culture to answer for itself.”

Shonkoff says what children really need are the basics, from day one.

“What kids need is to be in safe, stable, relatively predictable environments where there are opportunities to explore and learn, where the relationships are nurturing and stable, where the people you’re with are going to be here tomorrow and next week, and where you’re involved in individualized interactions and not just left alone plopped in front of the TV,” he says.

“That’s what the brain needs for healthy brain development.” And it doesn’t matter if it comes from daycare centers or at home with a parent or neighbor.

“Safety and stability is what the stress system needs. That can be provided in a home, in an informal childcare setting, in a formal preschool setting, in an intervention program, or in
an informal playgroup,” Shonkoff says. “The brain will do well with all of them. The science doesn’t tell you that you should be in a childcare center or in a preschool program or home with your mother. The science tells you about what the nature of the interaction should be and what produces healthy outcomes. The politics will decide how much money will go into each of these. Whether you do childcare or preschool or Head Start or you support mothers to be home with their kids, our role at the center is [to] say what the environment needs to look like in order to produce healthy outcomes. That’s our job.”

McCartney says parents don’t have to wait for the experts to tell them what to do.

“Everyday mundane acts offer opportunities for rich learning,” she says. “In a grocery store, for instance, a parent could ask what kind of food they need to make dinner. At the gas station, he or she could ask how many gallons it will take this time. Or on the walk home, a parent could ask the child what the most fun thing he or she had done that day. It’s socioemotional.”

As he continues to talk to the media and give lectures about this issue, Shonkoff says there’s no going back. No matter what the motivation is, we have to start paying more attention to really young children.

“Given what we know now about how much early experience affects learning and health outcomes, particularly given what we know about toxic stress and its impact, and knowing what we know about how serious adversity can undermine brain circuit formation in a young child, there’s a huge moral responsibility to do something,” he says. “We can’t just stand by and allow children to be damaged in this way. At the same time, it’s a huge social and economic investment issue, so whether you’re motivated by the moral responsibility as the right thing to do or the economic investment issue as the smart thing to do, in both cases, you end up with the same conclusion, which is investing in kids.

“Even as recently as five years ago, there were a lot of states in this country where, if you started to talk about what the government’s responsibility is for early childhood, it would be a conversation stopper,” Shonkoff says. “There were states that would say it’s an individual responsibility. The government has no business even talking about it. Now there isn’t a state in the country that isn’t trying to figure out what to do with its early childhood policies in terms of childcare or programs for very high-risk kids. And that’s a sea change. And it’s out of necessity. We know too much.”


Go to www.developingchild.harvard.edu for more information about the center. For extensive information about the science and policy of early childhood development, see the website of the National Scientific Council on the Developing Child, the center’s first major initiative.


About the Article

A version of this article originally appeared in the Spring 2007 issue of Ed., the magazine of the Harvard Graduate School of Education.

Respond to this story with an e-mail to the editor.


Photos by Tanit Sakakini

Ed Magazine: Spring 2007

Letters to the Editor


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