The term development refers to how people grow, adapt, and change over the course of their lifetimes, through physical development, personality development, socioemotional development, cognitive development (thinking), and language development. This chapter presents several major theories of human development including Jean Piaget's theory of cognitive and moral development, Lev Vygotsky's theory of cognitive development, Erik Erikson's theory of personal and social development, and Lawrence Kohlberg's stages of moral reasoning.

Children are not miniature adults. They think differently, they see the world differently, and they live by different moral and ethical principles than adults do. One of the first requirements of effective teaching is that the teacher understands how students think and how they view the world. Effective teaching strategies must take into account students' ages and stages of development.

The nature-nurture controversy asks the question, "Is development predetermined at birth, by hereditary factors, or do experience and other environmental factors affect it?" Today, most developmental psychologists believe that nature and nurture combine to influence biological factors playing a stronger role in some aspects, such as physical development, and environmental factors playing a stronger role in others, such as moral development. Today, most developmental psychologists acknowledge the role of a variable combination of both inborn factors and social experiences when explaining children's behavior.

Another issue revolves around the continuous and discontinuous theories, emphasizing how change occurs. One perspective assumes that development occurs in a smooth progression as skills develop and parents and the environment provide experiences. This continuous theory of development would suggest that children are capable of thinking and acting like adults, given the proper experience and education.

Piaget explored both why and how mental abilities change over time, assuming that the child is an active organism in this process. Thus, development in general depends on the child's active interaction with the environment according to Piaget, evidencing his direct application of biological principles and methods to formulate this theory.

Through the innate building of schemes or cognitive structures (patterns of behavior or thinking) along with the mental processes of adjusting these schemes called assimilation and accommodation, children interact and make sense of their environments. These scheme become a part of the older child when learning new ways of thinking that activate processes for handling imbalance (disequilibrium) to find new schemes or adaptations of old schemes to create balance (equilibrium). This process of restoring balance is called equilibration.

Piaget's theory of development represents constructivism, a view of cognitive development as a process in which children actively build systems of meaning and understandings of reality through their experiences and interactions. In this view, children actively construct knowledge by continually assimilating and accommodating new information.

Piaget divided the cognitive development of children and adolescents into four stages: sensorimotor, preoperational, concrete operational, and formal operational. He believed that all children pass through these stages in this order and that no child can skip a stage, although different children pass through the stages at somewhat different rates.

Neo-Piagetian theories are recent modifications of Piaget's theory that attempt to overcome the theory's limitations and address problems its critics have identified. In particular, neo-Piagetians have demonstrated that children's abilities to operate at a particular stage depend a great deal on the specific tasks involved; that training and experience, including social interactions, can accelerate children's development; and that culture has an important impact on development.

Lev Semionovich Vygotsky was a Russian psychologist who, though a contemporary of Piaget, died in 1934. His work was not widely read in English until the 1970s; however, and only since then have his theories become influential in North America. Vygotskian theory is now a powerful force in developmental psychology, and many of the critiques he made of the Piagetian perspective more than 60 years ago have come to the fore today.

Vygotsky's work is based on two key ideas. First, he proposed that intellectual development can be understood only in terms of the historical and cultural contexts children experience. Second, he believed that development depends on the sign systems that individuals grow up with: the symbols that cultures create to help people think, communicate, and solve problems-for example, a culture's language, writing system, or counting system.

In contrast to Piaget, Vygotsky proposed that cognitive development is strongly linked to input from others. Like Piaget, however, Vygotsky believed that the acquisition of sign systems occurs in an invariant sequence of steps that is the same for all children. Vygotsky's theory suggests that learning precedes development.

He believed that learning takes place when children are working within their zone of proximal development. That is, the zone of proximal development describes tasks that a child has not yet learned but is capable of learning at a given time. Some educators refer to a "teacher moment" when a child or group of children is exactly at the point of readiness for a given concept.

A key idea derived from Vygotsky's notion of social learning is that of scaffolding: the assistance provided by more competent peers or adults. Typically, scaffolding means providing a child with a great deal of support during the early stages of learning. A related concept is the cognitive apprenticeship.

How did Erikson view personal and social development? Like cognitive development, personal and social development are often described in terms of stages. At each stage, there are crises or critical issues to be resolved. Most people resolve each psychosocial crisis satisfactorily and put it behind them to take on new challenges, but some people do not completely resolve these crises and must continue to deal with them later in life. He listed 8 stages with explanations about what may usually be evidenced at each stage.

Piaget's theory of cognitive development also included a theory about the development of moral reasoning.. As with cognitive abilities, Piaget proposed that moral development progresses in predictable stages. Kohlberg's stage theory of moral reasoning is a refinement of Piaget's. Like Piaget, Kohlberg studied how children (and adults) reason about rules that govern their behavior in certain situations. Kohlberg proposed that people pass through a series of six stages of moral judgment or reasoning.

The main idea behind this chapter is the connection between the theories of development and the classroom environment. Educators may use these theories as guidelines for classroom management, developing character, and most importantly, the ongoing progression of cognitive development. No one theory will suffice, but a review of all theories and their interrelatedness will be able to offer improvement into the teaching/learning processes.