If you were to meet the child whom we call "Vicky," the first thing you would notice about her might be her cheerful, outgoing, humorous personality. She smiles and laughs often, greets the world like a friend, and would probably charm you with a joke or funny comment. The feature you might notice first about "Jason," a child of about the same age, is his physical agility. Wiry, flexi­ble, and strong, he is usually in motion—and a joy to watch.

Both these children, of course, have many other characteristics that make up their personalities, and these characteristics result from a great many influ­ences. Some of their traits—like Vicky's sense of humor and Jason's physical ability—are like those held by people closest to them: her father, his mother. Other traits seem to spring from nowhere. In any case, the blend of each child's physical, intellectual, and psychological characteristics is unique to that child. How did this blend come about? How did these children become the unique individuals they are? Which events in their lives have had the greatest influence? Which of their characteristics will persist into adulthood? Which will change? The answers to questions like these are what we seek when we study child development, the scientific study of normal changes in children over time.

We want to answer such questions for a host of reasons. First is basic curios­ity: for most of us, nothing is more interesting than understanding ourselves and the people we care about. By examining how children develop—from con­ception through adolescence—we will come to know more about ourselves and our fellow human beings. Second, the answers have practical benefits. When we understand how development occurs, we can step in to help people live hap­pier, more fulfilled lives. Finally, since no society can approach its potential unless its members fulfill their own, we help ourselves when we help others. Let us see, then, what this book is all about. 

Study of Child Development  

Each human being is like other people in some ways but unique in others. This book, too, is like other books about child development in some ways, but differ­ent in others—the topics it discusses, the way it treats them, how it illustrates and organizes them. Its singularity rests on how it reflects the point of view of each of its authors. To help readers assess what we say, we outline the perspec­tives from which we wrote this book. We start with our philosophical stance and go on to describe our more pragmatic concerns.

WE CELEBRATE HUMANITY
In a book about child development, it is not surprising that our emphasis is on what research and theory have to tell us about human beings. Whenever possi­ble, we cite research that has been performed on children rather than animals. Sometimes we need to refer to animal studies—for example, where ethical stan­dards prevent us from using children in research, as they would in explorations of possibly harmful consequences to the baby of a mother who takes drugs during pregnancy. When we do present conclusions based on animal research, we apply them with caution, since we cannot assume that they apply equally to humans.

Our primary interest, though, is in uniquely human qualities. Children are more adaptive than animals seem to be. They can imagine and pursue goals that animals cannot; they participate in a culture in ways that animals do not. These powers make the study of child development more complex than it otherwise would be. And we celebrate that complexity because it reflects the richness of humanity.

In keeping with this viewpoint, we have included a number of boxes titled "Around the World."* These boxes briefly explore the diversity and complexity of child development in other cultures. They pose a warning to us as scientists: when it comes to understanding humanity, we must look to its richness before we can find any unifying simplicity.

WE BELIEVE IN THE RESILIENCE OF CHILDREN

We do not believe that a passing event or experience can easily ruin the rest of a child's life. Yes, one especially traumatic incident or a pattern of deep depriva­tion in childhood may well have grave and long-lasting consequences. How­ever, the stories of countless people, some of whom have been followed by researchers from childhood into middle or old age, teach us that later events can often transform the results of early experiences. In most cases, one experience is unlikely to cause irreversible damage, and a nurturing environment can often help a child overcome the effects of early deprivation. Studies of children on the Hawaiian island of Kauai, for example, have reinforced our
belief in children's resilience by showing that even when children have been seriously injured at birth, the best predictor of development is the nature of the experiences the children have had while growing up (E. Werner, 1985). 

WE RECOGNIZE THAT CHILDREN
HELP SHAPE THEIR OWN DEVELOPMENT  

Children are not passive recipients of influences. They help shape their own environment, and then they respond to the environmental forces that they have helped bring about. In other words, influences are bidirectional, flowing from the outside world to the child—and from the child to the child's world. Beginning at birth, babies' inborn traits influence the ways parents and other people react to

*See the list of boxes on pages xvii-xx.