able human beings to explore and learn about the world around us emerge and become remarkably sophisticated. The child becomes a social being with an array of deeply important relationships. Language is acquired and powerful communicative capacities develop. And, the child's emotional repertoire and awareness grow to encompass both tremendous joy and deep sadness. The tasks to be accomplished range from developing day-night rhythms to acquiring a rudimentary moral code to learning how to negotiate and sustain friendships.

At the same time, virtually no one argues that a given child's life course is set by the time of school entry. People are not like rockets whose trajectory is established at the moment they are launched. Indeed, it is the lifelong capacity for change and reorganization that renders human beings capable of dramatic recovery from early harm and incapable of being inoculated against later adversity. This lifelong plasticity renders us both adaptive and vulnerable.

Development depends on both stability and flexibility—it is not a zero-sum game that sets the importance of the early years against the value of the later years. The real question is not which matters more—early or later experience—but how is later experience influenced by early experience? This directs attention to the early childhood years not because they provide an unalterable blueprint for adult well-being, but because what is learned at the beginning of life establishes a set of capabilities, orientations to the world, and expectations about how things and people will behave that affect how new experiences are selected and processed. The infant who has learned that he can engage his parent in play and make objects do what he wants them to do acquires a fundamental belief in his ability to affect the world around him. The toddler who has learned that the people she depends on for comfort will help her when she is distressed is more likely to approach others with empathy and trust than the toddler whose worries and fears have been dismissed or belittled. The preschooler who has routinely cuddled into an adult's lap and read books before going to bed is more likely to enter kindergarten with a keen interest in reading. The child who has missed these experiences may have a hard time recapturing them later in life. In short, getting off to a good start in life is a strategy for increasing the odds of greater adult competence.

What do we know about how many young children are getting off to a good start? It would seem logical in a report of this nature to include information about trends in the well-being of young children. In fact, as a nation, we have surprisingly little information of this nature. We know far more about trends in the conditions, such as poverty and use of child care (see Part III), that affect young children than we do about the children themselves.

The data that are available present a very mixed picture (for an excel-

lent overview, see U.S. Department of Health and Human Services, 1999a). While the nation has made impressive inroads in reducing infant mortality, rates of premature births and low-birthweight babies are increasing (see Chapter 8). Among other health indicators (not covered in this report), immunization rates have increased and lead exposure and unintentional injuries have declined substantially, but the percentage of young children living in poverty with activity limitations has risen and the incidence of asthma and chronic sinusitis has increased substantially for all children. The incidence of overweight school-age children is increasing, but data are not available on children under age 6. While there are a few signs that young children's early literacy is improving, the positive trends appear only for children who are not growing up in poverty and whose parents speak English as their native language (see Chapter 6). Rates of child abuse and neglect have remained constant for children under age 6 over the past decade (see Chapter 9). We know virtually nothing about trends in the incidence of mental health or behavioral problems affecting young children. Many groups before us have highlighted the tremendous need for better early childhood indicators in this country (see Hauser et al., 1997; National Research Council and Institute of Medicine, 1995a), for two recent reports on this issue); and we enthusiastically concur.

Developmental science does, however, allow us to address the question of what getting off to a good start means, and it can guide efforts to improve the nation's data on young children. These are the issues that we address in this part of the report. What are the most significant developmental changes that occur during these early years and that, if absent or seriously delayed, are cause for concern? What early experiences foster these developments, which undermine them, and how might this differ for different children?

There are libraries full of books on child development. Our intent was not to produce a comprehensive handbook that describes every facet of early development or a guide for parenting that addresses every milestone. Our review was more circumscribed. We sought to identify and discuss early developmental tasks that, if mastered, appear to get children started along adaptive pathways and, if seriously delayed or problematic, can lead a child to falter. We drew heavily on the legacy of research that has followed children over time, starting in infancy and preschool, to discern early precursors of later (and even lifelong) resilience and sustained competence (see Anthony and Cohler, 1987; Egeland et al., 1993; Garmezy and Rutter, 1983; Masten, 1994; Rutter, 1994; Werner, 1995, 2000). The internal resources and capabilities and external supports that characterize children who develop well despite adversity struck us as a fitting departure point for the exploration of the significant accomplishments of the early childhood years. Others have conducted similar reviews in recent years (see Carnegie

Task Force on Meeting the Needs of Young Children, 1994; Damon, 1998; Ramey and Ramey, 1999), and we benefited tremendously from their work as well. This led us to emphasize three domains among the many accomplishments that characterize the years from birth to age 5:

• Negotiating the transition from external to self-regulation, including learning to regulate one's emotions, behaviors, and attention. This captures the emergence of self-control and independence and can provide an analogy for the movement toward competent functioning that characterizes development as a whole (Chapter 5).

• Acquiring the capabilities that undergird communication and learning. This includes the early development of language, reasoning, and problem solving (Chapter 6).

• Learning to relate well to other children and forming friendships. This highlights the emerging capacity to trust, to love and nurture, and to resolve conflict constructively (Chapter 7).

The behavioral evidence on these topics provides a rich portrait of how early development unfolds in interaction with people, things, places, and events; the conditions under which it appears to get off track; and the factors that seem to make a difference in whether the child is equipped to learn, make friends, and enjoy life as a 5-year-old. We close this part by looking inward at the developing brain (Chapter 8). Not only has the research on early brain development generated tremendous public excitement, but it also complements what we have learned from behavioral research and points to some areas of special concern. Considered together, these two streams of behavioral and neuroscience research offer a fuller portrait of early childhood than does either one considered alone.

Human infants start life as remarkably helpless individuals who elicit powerful protective responses from their caregivers. On their own, they would die. In relationships with protective, nurturing adults, they thrive. Supporting their development, however, requires sustained patience and adaptation as infants move gradually and unevenly from needing help in order to do anything, to doing—and even insisting on doing—many things for themselves. Scientists have found it useful to capture this transition from helplessness to competence in terms of the child's growing regulatory capacity. What does this mean? Initially, it refers to the mastery of tasks that were accomplished by the mother's body or in concert with the mother's body when the child was in the womb, but now must be accomplished by the child's body and through signaling needs to responsive adults. These tasks include everything from maintaining a normal body temperature to orchestrating physiology and behavior to conform to the day-night rhythm of human existence, to learning to soothe and settle once basic needs are met. Later, it means developing the capacity to manage powerful emotions constructively and keep one's attention focused. This chapter addresses these regulatory tasks.

Regulation cuts across all aspects of human adapatation. Living and learning require people to react to changing events and then to regulate their reaction. The capacity to react and the toll that reaction takes depend on the capacity to recover from the reactions. For example, getting upset by things that are upsetting can be very useful. It motivates people to act to make life better. But staying upset, ruminating, or carrying negative emo-