Chapter 11 Introduction

Boy: Tom Fullum/Photographer’s Choice RF/Getty Images; landscape: Paul Carroll and Mhairi Carroll/Flickr/Getty Images
Licensed Material is being used for illustrative purposes only; person depicted in the licensed Material is a model.

When I (Peter Gray) first saw my newborn son, my words did not match my thought. I said something like, “Oh, he’s beautiful,” but my thought was, “My goodness, will he turn into a real human being?” Of course, I knew intellectually that he already was a human being, but at the moment he looked more like a cross between that and a garden slug.

Over the next weeks, months, and years the little slug’s mother and I watched in amazement as he grew not only to look increasingly human but also to do the things that humans everywhere do. He began to smile in response to our smiles; he began eventually to walk upright on two legs and to talk, sometimes incessantly; and, true to his species’ name (Homo sapiens, where sapiens means “wise”), he manifested from early on an insatiable curiosity and soon developed a remarkable store of knowledge and theories about his world.

This chapter is about the millions of new human beings who enter the world every year. More specifically, it is the first of two chapters concerned with developmental psychology, the study of changes that occur in people’s abilities and dispositions as they grow older. Some developmental psychologists study changes that occur in adulthood (as you will discover in Chapter 12), but most study changes that occur in infancy and childhood. They do so not only because they find infants and children fascinating and worthy of understanding for their own sake, but also because they see in infants and children the origins of adult abilities. Human thought and language in particular are extraordinarily complex, and developmental psychologists have learned a great deal about them by watching them grow in infants and children.

Another reason to study development is to gain an understanding of the mechanisms underlying behavior. Are animals, including people, the product of their genes, or are they shaped by their environments? Clearly, as we’ve already seen in other chapters in this book (especially Chapter 10 in discussing intelligence), neither extreme version of this nature-nurture debate is plausible. It is plausible, however, to ask, “How do nature and nurture interact to produce a particular psychological outcome?” and the only way this question can be answered is by looking at development.

The chapter begins by looking at physical development, focusing especially on the prenatal period and then puberty. We then examine how infants learn about the physical world. We turn next to some theories and research concerning the development of reasoning, including reasoning about people’s minds as well as about physical objects. Finally, we discuss the acquisition of language. A theme throughout is that children’s own exploratory and playful activities are prime forces for their mental development. Through play and exploration, in a responsive social environment, children acquire the abilities and knowledge that enable them to survive and thrive in the world into which they are born.