Psychology: Development

Development

For their first few months, chimpanzee babies are muchbetter company than human infants. Chimps cry less, fuss less, and drool less. They’re strong enough to support their heads and to ride, unassisted, on their moth-ers’ bodies. When so inspired, they can even climb trees and swing from high branches. Human infants, in contrast, can’t even hold up their heads, let alone cling to mom. They usually need a whole year to master the art of walking, and even then their gait resembles that of a slightly drunk person.

But as the weeks pass, we begin to see that lurking inside that chubby body is a sophisticated physicist, a subtle psychologist, and a versatile linguist. As the infant carefully watches the world, the world, in turn, is working on her psyche, teaching her how things fit together and how they fall apart; whom to trust and whom to avoid; what she can do with her building blocks and what to call the thing that barks. She is not only beginning to master the functions of her mind and body and the features of her environment, but also starting to understand the psyches of others—a skill known as having a theory of mind. This skill will enable her to work with fellow humans to imagine, plan, create, build, and do all the other things of which her species is capable. And the rest, as they say, is history—the history of the development of a single human being.

In this, we’ll consider what developmental psychologists have learned by studying all of these forms of development—physical and sensorimotor (changes in the body and the ability to sense and move), cognitive (growth in knowledge and intellectual skills), and socioemotional (growth in the skills needed to perceive, under-stand, and get along with others). And we’ll see how changes in each one of these domains affect all the others, as when physical changes in the brain enable new modes of thinking and self control, which in turn support new ways of interacting with others.

At the same time, people are not just empty vessels into which the world pours its wis-dom. To the contrary, a new generation of psychologists is showing that the mind comes wired with many ideas about the physical, social, and psychological worlds. As shows, those ideas continue to mature and change as development unfolds—through the social and cognitive flowering of childhood; to the risk-taking, back-talking tumult of adolescence; to the application of our knowledge throughout adulthood into old age.

Of course, nature cannot unfold without nurture, genes require environments to be expressed, and the individual needs other people to be fully realized. Accordingly, each of us provides part of the context in which others develop. As anyone who has fetched a child’s thrown toy a dozen times can attest, children aren’t just hanging out and growing up—they actively shape their environments. At the other end of the life span, our grandparents aren’t just biding time in their rocking chairs. Rather, through the stories they tell, the examples they enact, and the things they create, they actively transmit the cultures of which they have been a part.

In William Shakespeare’s As You Like It, the melancholy Jacques famously says, “All the world’s a stage / And all the men and women merely players; / They have their exits and their entrances, / And one man in his time plays many parts / His acts being seven ages.” Developmental psychologists might disagree about the stages of human development, but all agree that a person “plays many parts” across the lifespan.