Developmental Psychology: Understanding the Forces that Shape Us

We are constantly changing, throughout our lives. We are not only the people we are today but also the people we were yesterday and the people we will become tomorrow. The thread of continuity that runs through our lives is real, but we change more than we realize. To fully understand ourselves, we must understand the processes of change and continuity in our lives. Psychologists refer to this as development.

In the past, psychologists differed on the question of how much of our development is biologically determined or shaped by the learning environment. However, today, psychologists agree that development is the product of the combined forces of "nature" (biology) and "nurture" (environment). Developmental psychology is the field of psychology that focuses on development across the lifespan. To understand human beings, we need to understand how they change across their lifespan. Just as we cannot understand butterflies without understanding their metamorphosis from caterpillars, we cannot understand human beings without understanding the processes of development. Developmental psychology looks at the factors that play key roles in the process of development. As expected, not all psychologists agree about these factors. In this section, we will look at the factors that play key roles in the process of development.

Nature and Nurture are two significant factors that influence our actions, thoughts, and feelings. Language provides a good example of the rich interplay of nature and nurture in our lives. Although experience is essential in language development, children will learn to use language only if they are exposed to it. Furthermore, they will learn to speak the language to which they are exposed. Children cannot use a baseball glove correctly unless they have seen others play ball (nurture). But you cannot effectively teach children to do much with a glove until age 4 or so after considerable physical development has taken place (nature). We are creatures of complex combinations of both our nature and nurture.

Maturation, the systematic physical growth of the nervous system and other bodily structures, is the most critical aspect of nature (biological factors) in the study of development. How much of the change that we see occurring with age is the result of physical maturation? Although both experienced and maturation are essential in most developmental changes, maturation is surprisingly important in many specific contexts. For example, successful toilet training is difficult for most children before the age of 24 months, because they are not maturational ready to learn that task.

In addition, early experience and critical periods play a significant role in development. Critical periods are times when specific experiences must occur for normal development to continue. For example, if a person does not receive adequate visual stimulation during the critical period of visual development, he or she may suffer from visual deficits throughout life. The critical period for language development appears to be between the ages of 2 and 13. Early Experience and Critical Periods Imprinting. The Puritans believed that childhood experiences shape our adult behavior. This belief is still held by many today, but is it true? Research on animals shows that they have an inborn tendency to follow their mothers, but can also learn to follow any moving, noisy object. This type of learning is called imprinting and can only occur during a critical period of the animal's life. Humans do not experience imprinting, but we do form attachments to our caregivers through prolonged experience with them.

Early social deprivation is also a crucial factor that affects development. Infants who do not receive adequate social stimulation during their first year of life may become withdrawn, listless, and unresponsive. Children who have experienced extreme social deprivation, such as those raised in orphanages, may suffer from emotional, social, and cognitive deficits that persist throughout their lives. Stage theories of development: Stage theories of development are a popular approach in psychology that explain how people change over time. Stage theorists believe that the changes that occur from one stage to the next make individuals qualitatively different from how they were at the previous stage. These changes open up new experiences and possibilities. The changes are also believed to be biologically programmed to unfold in a fixed sequence in all normal individuals. Stage theorists also believe that a child cannot progress to the next stage until the current one has been mastered. However, they recognize that the transition from one stage to the next is a gradual blending.

One of the most well-known stage theories is Jean Piaget's stage theory of cognitive development. Piaget distinguished four major stages of cognitive development, Piaget's theory shows that children's cognitive capacities develop rapidly until puberty but change little after that. On average, children progress from individuals who cannot reason in mental symbols to individuals fully capable of adult reasoning in 11 short years.

Two theorists have provided stage theories of moral development that are related to Piaget's theory of cognitive development. Lawrence Kohlberg's theory of moral development is one of the two theories. Kohlberg collected data for his stage theory of moral development by presenting boys with moral dilemmas and asking for evaluations of the people and actions involved. Kohlberg sees the first two major shifts in moral reasoning as occurring at the same time as the beginnings of the preoperational and concrete operational stages in Piaget's theory of cognitive development. Kohlberg concludes that we engage in little principled moral reasoning until age 13, and very few of us ever make it to a stage in which we reason mostly in principled ways. Carol Gilligan proposed a theory about how girls develop morals differently than boys. She argued that girls move through stages that focus on people's needs rather than abstract concepts. Gilligan suggests that there are three stages of moral development for girls, which are different from Kohlberg's theory. These stages center on balancing self-interest with concern for others' welfare. Gilligan's theory raises questions about how Heinz's actions would be judged at each stage of moral development

In addition to cognitive and moral development, stage theories also apply to personality development. Erik Erikson's stage theory of psychosocial development suggests that we experience eight stages of development throughout our lives, each with a unique psychosocial crisis. These eight stages are trust vs. mistrust, autonomy vs. shame and doubt, initiative vs. guilt, industry vs. inferiority, identity vs. role confusion, intimacy vs. isolation, generativity vs. stagnation, and integrity vs. despair. Each stage builds on the previous one, and the successful resolution of each stage leads to the development of a healthy personality.

Stage theories of development provide a useful framework for understanding how people change over time. These theories recognize that changes occur gradually, yet they still believe that individuals go through a series of abrupt changes or stages. Stage theories of cognitive development, moral development, and personality development provide insight into how we develop across different domains throughout our lives. While stage theories are not without criticism, they continue to be valuable tools for understanding human development. In the next article, we will talk about human development through the years in The Incredible Journey of Human Development: From Prenatal to Infancy