The Road to a New Energy System: Mobilizing Science to Revitalize Early Childhood Policy

These core concepts constitute a rich return on decades of public investment in scientific research. This evolving knowledge base has informed the development, implementation, and evaluation of a multitude of intervention models aimed at improving early childhood development during the past 40 years. The theory of change that currently drives most early interventions for children living in adverse circumstances, which typically involve poverty, emphasizes the provision of enriched learning opportunities for the children and a combination of parenting education and support services for their families, focused mostly on mothers. This model has been implemented successfully in a number of flagship demonstration projects, such as the Perry Preschool and Abecedarian projects, each of which has confirmed that effective intervention can produce positive effects on a range of outcomes. Documented benefits include higher rates of high-school graduation and increased adult incomes, as well as lower rates of special education referral, welfare dependence, and incarceration.

Persistent challenges, however, lie in the magnitude of the effects that have been achieved, which typically falls within the mild to moderate range, as well as in the marked variability in measured outcomes, which is associated largely with inconsistent quality in program implementation. In order to address these challenges effectively, early childhood policy must be driven by two fundamental directives. The first will help to close the gap between what we know and what we can do right now to promote better developmental outcomes. The second calls for new ideas. Both are essential. These directives are:

Decades of program evaluation indicate that the quality of early childhood investments will determine their rate of return. Programs that incorporate evidence-based effectiveness factors that distinguish good services from bad will produce positive outcomes. Programs with inadequately trained personnel, excessive child/adult ratios, and limited or developmentally inappropriate learning opportunities are unlikely to have significant effects, particularly for the most disadvantaged children. The strongest data on positive effects come from a few model programs that are based on a clear theory of change that matches the nature of the intervention to explicit child and family needs. The dilemma facing policymakers is the debate about the relative effectiveness of current programs that vary markedly in the skills of their staff and the quality of their implementation. Overcoming that variability is the most immediate challenge. Continuing to invest in programs that lack sufficient quality is unwise and unproductive.

The most effective early childhood programs clearly make a difference, but there is considerable room for improvement and a compelling need for innovation. For example, 40 years of follow-up data from the most frequently cited preschool program, the Perry Preschool Project, reveal increased rates of high-school graduation (to 66% from 45%) and lowered rates of arrest for violent crime (to 32% from 48%) that represent impressive results with large benefit/cost ratios. But it is impossible to look at this intervention model, which results in only two of three participants completing high school and one-third committing violent crimes, and conclude that the remaining challenge is simply a matter of expanded funding for replication. The data clearly demonstrate that improved interventions are needed. Meeting this need will require the nation to build on current best practices and draw on strong science to develop innovative interventions that get a bigger bang for the buck.

Promising new directions

With this challenge in mind, two areas of scientific inquiry are particularly ripe for development. First, achieving a deeper understanding of the biology of adversity and the evidence base regarding effective interventions would help in fostering innovative policies and programs for children and families whose life opportunities are undermined by toxic stress. Toxic stress differs markedly from other types of stress, called positive or tolerable, in terms of the distinctive physiological disruptions it triggers in the face of adversity that is not buffered by protective relationships.

Positive stress is characterized by moderate, short-lived increases in heart rate, blood pressure, and levels of stress hormones, such as cortisol and inflammatory cytokines, in response to everyday challenges such as dealing with frustration, meeting new people, and getting an immunization. The essential characteristic of positive stress in young children is that it is an important aspect of healthy development that is experienced in the context of stable, supportive relationships that facilitate positive adaptation.

Tolerable stress is a physiological state that could potentially disrupt brain architecture through, for example, cortisol-induced disruption of neural circuits or neuronal death in the hippocampus. Causes of such stress include the death or serious illness of a parent, family discord, homelessness, a natural disaster, or an act of terrorism. The defining characteristic of tolerable stress is that protective relationships help to facilitate adaptive coping that brings the body’s stress-response systems back to baseline, thereby protecting the brain from potentially damaging effects, such as those associated with post-traumatic stress disorder.

Toxic stress comprises recurrent or prolonged activation (or both) of the body’s stress-response systems in the absence of the buffering protection of stable adult support. Major risk factors in early childhood include deep poverty, recurrent maltreatment, chronic neglect, severe maternal depression, parental substance abuse, and family violence. The defining characteristic of toxic stress is that it disrupts brain architecture and affects multiple organ systems. It also leads to relatively lower thresholds for physiological responsiveness to threat that persist throughout life, thereby increasing the risk for stress-related chronic disease and cognitive impairment.

This simple taxonomy, proposed by the National Scientific Council on the Developing Child, differentiates normative life challenges that are growth-promoting from significant adversities that threaten long-term health and development and therefore call for preventive intervention before physiological disruptions occur. Within this taxonomy, programs that serve children whose well-being is compromised by the generic stresses of poverty have demonstrated greater effectiveness than have programs for children whose development is threatened further by additional risk factors, such as child maltreatment, maternal depression, parental substance abuse, family violence, or other complex problems that few contemporary early care and education programs have the specialized expertise needed to address effectively. This gap can be seen when highly dedicated yet modestly trained paraprofessionals are sent to visit the homes of deeply troubled families with young children whose problems overwhelm the visitors’ limited skills. Of perhaps greater concern, children and parents from highly disorganized families struggling with mental illness and substance abuse are less likely to participate in any formal early childhood program and are more likely to drop out if they are enrolled. Thus, significant numbers of the most disadvantaged young children who are at greatest risk for school failure, economic dependence, criminal behavior, and a lifetime of poor health are neither reached nor significantly helped by current programs.

One promising route that innovation in early childhood policy might pursue is illustrated by the efforts of scientists in the Division of Violence Prevention at the federal Centers for Disease Control and Prevention, who are reconsidering child abuse and neglect as a public health issue rather than as a social services concern. This shift in perspective incorporates new research about the extent to which early maltreatment gets built into the body and leads not only to impairments in learning but also to higher rates of diabetes, heart disease, hypertension, substance abuse, depression, stroke, cancer, and many other adult diseases that drive escalating health care costs. The high prevalence of child abuse and neglect alone, estimated to affect 7.5% of children aged 2 to 5, is arguably one of the most compelling threats to healthy child development and certainly the most challenging frontier in early childhood policy.

Since their establishment more than a century ago, child welfare services have addressed the needs of abused and neglected children by focusing on physical safety, reduction of repeated injury, and child custody. But advances in neuroscience now indicate that evaluations of maltreated children that rely exclusively on physical examination and x-rays are woefully insufficient. They must be augmented by comprehensive developmental assessments of the children and sophisticated evaluations of the parent-child relationship by skilled examiners. Moreover, when foster care arrangements are deemed necessary, the need for additional intervention for the child and specialized support for the foster parent is often not recognized. Consequently, the current gap between what is known and what is done for children who have been maltreated may well be the greatest shortcoming in the nation’s health and human services system. Because incremental improvements in child welfare systems have been difficult to achieve, dramatic breakthroughs will require creative thinking, scientific justification, and strong leadership committed to bold change.

The second promising area for scientific inquiry—creatively applying new knowledge from the growing science of early learning, beginning in infancy and extending to school entry—would enhance the effects of early care and education programs for all children, and programs for disadvantaged youngsters would be especially strengthened. To achieve this goal, it will be necessary to think beyond the emphasis on language stimulation and early literacy that informs current practice—efforts that certainly should be continued—and to develop innovative teaching strategies that target other domains of development that are essential for success in school, at work, and in the community. This will mean focusing on the early emergence of competencies in areas known as executive functioning, such as working memory, attention, and self-regulation, that contribute to the ability to plan, use information creatively, and work productively with others.

Additional efforts also will be needed to integrate programs that target the emotional and social needs of young children into the broader early care and education environment. Indeed, failure to acknowledge the interrelatedness of cognitive, language, emotional, and social capabilities, in skill development and in their underlying brain architecture, undermines the full promise of what evidence-based investments in early learning might achieve. The conventional approach to this challenge focuses on treating behavioral problems and emotional difficulties as they become apparent. Yet advances in evidence-based preventive interventions offer much promise in the early childhood years, particularly when combined with the skills and commitment required to address the mental health needs of parents as well. Promising areas for creative intervention include adopting preventive approaches that do not require the assignment of clinical diagnoses to young children and providing health professionals who typically work outside of the mental health field with the skills they need to address, or at least identify, the mental health needs of their patients.

Key policy opportunities

Within the evolving context of current early childhood policy, the creative mobilization of scientific knowledge offers an opportunity to close the gap and create the future in three important areas.

The dilemma facing policymakers is the debate about the relative effectiveness of current programs that vary markedly in the skills of their staff and the quality of their implementation. Overcoming that variability is the most immediate challenge. Continuing to invest in programs that lack sufficient quality is unwise and unproductive.

First, the nation would benefit from a more enlightened view of public expenditures for high-quality early care and education programs in the first five years of life as an investment in building a strong foundation for later academic achievement, economic productivity, and responsible citizenship, and not as a burdensome subsidy for places to watch over children of working parents at the lowest possible cost. The evidence is clear that positive early learning experiences are beneficial for children at all income levels, and strategic investments in youngsters from disadvantaged families yield the largest financial returns to society. The coordination of effective developmental programs with primary health care and interventions that enhance economic security can further increase the odds of more favorable outcomes for children living in poverty. A regular source of health care, for example, increases the likelihood that a young child’s developmental progress can be monitored, concerns can be identified early, and effective interventions can be provided when needed. Linking innovative services that bolster parent employment, income, and assets presents another promising strategy for strengthening family resources, both human and material, that are associated with more favorable child outcomes.

Second, specialized interventions as early as possible, at or before birth, should be focused on improving life outcomes for children whose learning capacity and health are compromised by significant adversity above and beyond the burdens of poverty alone. As described above, the physiological effects of excessive or chronic activation of the stress-response system can disrupt the developing architecture of the immature brain. This can be particularly problematic during sensitive periods in the formation of neural circuits affecting memory in the hippocampus and executive functioning in the prefrontal cortex. In a parallel fashion, the wear and tear of cumulative stress over time can result in damage to the cardiovascular and immune systems that may help explain the association between adverse childhood experiences and greater prevalence of chronic disease in adulthood.

Third, significant social and economic benefits to society could be realized from greater availability of effective prevention and treatment services for young children with emotional or behavioral problems, along with increased assistance for parents and nonrelated caregivers whose own difficulties with depression adversely affect a young child’s environment of relationships. This area of unmet need has been underscored in recent years by media reports and empirical evidence of young children being removed from child care centers and preschool programs that are ill-equipped to deal with behavior problems that undermine learning. Several studies by the National Academies offer a wealth of knowledge to address this challenge. The Institute of Medicine’s 1994 report Reducing Risks for Mental Disorders emphasizes the difference between preventing and treating mental health problems and highlights the promise of prevention. A 2009 report from the National Research Council and Institute of Medicine, Preventing Mental, Emotional, and Behavioral Disorders Among Young People, summarizes the extensive progress that has been made in the development and evaluation of a broad array of evidence-based preventive services during the past decade and notes that the data on benefit/cost analyses have been most positive for interventions in the early childhood years.

Taken together, these priority areas reinforce the importance of early childhood policies that focus on both children and parents, but they also highlight the extent to which current interventions are often too limited. For example, families who must deal with the daily stresses of poverty and maternal depression need more help than is typically provided by a parent education program that teaches them the importance of reading to their children. Youngsters who are struggling with anxiety and fear associated with exposure to violence need more than good learning experiences during the hours they spend in a preschool program. Families burdened by significant adversity need help to achieve greater economic security, coupled with access to structured programs, beyond current informal efforts, that focus on the mental health needs of adults and children. Such two-generational models of intervention must be implemented by personnel with sufficient expertise to deal with the problems they are asked to address.

Finally, continuing debate in the world of early childhood policymaking raises important questions about the definition of “early.” Neuroscience tells us that infants and toddlers who experience toxic stress are at considerable risk for disrupted neural circuitry during early sensitive periods of brain development that cannot be rewired later. This would suggest that later remediation for children who are burdened early on by the physiological effects of toxic stress will be less effective than preventive intervention at an earlier age. Other observers point toward the positive effects of preschool education beginning at age four and argue that missed learning opportunities during the infant and toddler period can be remediated by enrichment in the later preschool years, thereby saving earlier program expenses. Whether broad-based investments are made earlier or later, the long-term societal costs associated with significant early adversity underscore the potential benefits of beginning interventions as early as possible for the most vulnerable young children.

Reasons for optimism

Although serious challenges remain, public understanding of the importance of the early years has grown considerably during the past decade. This increasing awareness is grounded in a greater appreciation of the extent to which early experience influences brain architecture and constructs a foundation for all the learning and health that follow.

Science has been quite effective in answering the question of why public funds should be invested in the healthy development of young children. In contrast, however, science has been less conclusive in its answers to the how questions, which are now primed to be addressed at a much more focused and rigorous level. The challenge is straightforward and clear: to move beyond the simple call for investing in the earliest years and to seek greater guidance in targeting resource allocation to increase the magnitude of return. A 2000 report from the Institute of Medicine and the National Research Council, From Neurons to Neighborhoods: The Science of Early Childhood Development, articulated this challenge: “Finally, there is a compelling need for more constructive dialogue between those who support massive public investments in early childhood services and those who question their cost and ask whether they really make a difference. Both perspectives have merit. Advocates of earlier and more intervention have an obligation to measure their impacts and costs. Skeptics, in turn, must acknowledge the massive scientific evidence that early childhood development is influenced by the environments in which children live.”

Pretending that the early years have little impact on later life outcomes is no longer a credible position. Contending that full funding of existing early childhood programs will completely eliminate later school failure and criminal behavior is similarly indefensible. The concept of early intervention as a strategy for improving life outcomes for young children is well grounded in the biological and social sciences, but the translation of that concept into highly effective programs that generate strong returns on investment needs more work. For those who insist that the United States can do better, current practice provides a good place to start.

If the nation is ready to support a true learning environment that makes it safe for policymakers, practitioners, researchers, and families to ask tough questions, experiment with new ideas, learn from failure, and solve problems together, then the benefits of a more prosperous, cohesive, and just society surely lie ahead.

Recommended reading

Center on the Developing Child, A Science-Based Framework for Early Childhood Policy: Using Evidence to Improve Outcomes in Learning, Behavior, and Health for Vulnerable Children (Cambridge, MA: Harvard University, 2007) ().

Committee on Prevention of Mental Disorders, Division of Biobehavioral Sciences and Mental Disorders, Institute of Medicine, Reducing Risks for Mental Disorders: Frontiers for Preventive Intervention, eds. P. Mrazek and R. Haggerty (Washington, DC: National Academy Press, 1994).

J. Isaacs, Impacts of Early Childhood Programs (Washington, DC: First Focus and the Brookings Institution, 2008).

L. A. Karoly, M. R. Kilburn, and J. S. Cannon, Early Childhood Interventions: Proven Results, Future Promise (Santa Monica, CA: RAND Corporation, 2005).

E. Knudsen, J. Heckman, J. Cameron, and J. Shonkoff, “Economic, Neurobiological and Behavioral Perspectives on Building America’s Future Workforce,” Proceedings of the National Academy of Sciences 103 (2006): 10155–10162.

J. Middlebrooks and N. Audage, The Effects of Childhood Stress on Health Across the Lifespan (Atlanta, GA: Centers for Disease Control and Prevention, National Center for Injury Prevention and Control, 2008).

Committee on Integrating the Science of Early Childhood Development; Board on Children, Youth, and Families; Commission on Behavioral and Social Sciences and Education; National Research Council and Institute of Medicine, From Neurons to Neighborhoods: The Science of Early Childhood Development, eds. J. Shonkoff and D. Phillips (Washington, DC: National Academy Press, 2000).

Committee on Prevention of Mental Disorders and Substance Abuse Among Children, Youth and Young Adults: Research Advances and Promising Interventions; Board on Children, Youth, and Families; Division of Behavioral and Social Sciences and Education; National Research Council and Institute of Medicine, Preventing Mental, Emotional, and Behavioral Disorders Among Young People: Progress and Possibilities, eds. M. O’Connell, T. Boat, and K. Warner (Washington, DC: National Academy Press, 2000).

National Scientific Council on the Developing Child, Excessive Stress Disrupts the Architecture of the Developing Brain (Working Paper No. 3, 2005) ().

National Scientific Council on the Developing Child, The Science of Early Childhood Development: Closing the Gap Between What We Know and What We Do (2007) ().

J. Shonkoff, W. T. Boyce, and B. McEwen, “Neuroscience, Molecular Biology, and the Childhood Roots of Health Disparities: Building a New Framework for Health Promotion and Disease Prevention,” Journal of the American Medical Association 301, no. 21 (2009): 2252–2259.

Jack P. Shonkoff () is the Julius B. Richmond FAMRI Professor of Child Health and Development and founding director of the Center on the Developing Child at Harvard University.

Cite this Article

Shonkoff, Jack P. “The Road to a New Energy System: Mobilizing Science to Revitalize Early Childhood Policy.” Issues in Science and Technology 26, no. 1 (Fall 2009).

Vol. XXVI, No. 1, Fall 2009