Cognitive Development

The development of thought processes, including remembering, problem solving, and decision-making, from childhood through adolescence to adulthood.

Historically, the cognitive development of children has been studied in a variety of ways. The oldest is through intelligence tests, such as the widely used Stanford Binet Intelligence Quotient, or IQ, test first adopted for use in the United States by psychologist Lewis Terman (1877-1956) in 1916 from a French model pioneered in 1905. IQ scoring is based on the concept of "mental age," according to which the scores of a child of average intelligence match his or her age, while a gifted child's performance is comparable to that of an older child, and a slow learner's scores are similar to those of a younger child. IQ tests are widely used in the United States, but they have come under increasing criticism for defining intelligence too narrowly and for being biased with regard to race and gender. In contrast to the emphasis placed on a child's native abilities by intelligence testing, learning theory grew out of work by behaviorist researchers such as John Watson and B.F. Skinner (1904-1990), who argued that children are completely malleable. Learning theory focuses on the role of environmental factors in shaping the intelligence of children, especially on a child's ability to learn by having certain behaviors rewarded and others discouraged.

The most well-known and influential theory of cognitive development is that of French psychologist Jean Piaget. Piaget's theory, first published in 1952, grew out of decades of extensive observation of children, including his own, in their natural environments as opposed to the laboratory experiments of the behaviorists. Although Piaget was interested in how children reacted to their environment, he proposed a more active role for them than that suggested by learning theory. He envisioned a child's knowledge as composed of schemas, basic units of knowledge used to organize past experiences and serve as a basis for understanding new ones. Schemas are continually being modified by two complementary processes that Piaget termed assimilation and accommodation. Assimilation refers to the process of taking in new information by incorporating it into an existing schema. In other words, we assimilate new experiences by relating them to things we already know. On the other hand, accommodation is what happens when the schema itself changes to accommodate new knowledge. According to Piaget, cognitive development involves an ongoing attempt to achieve a balance between assimilation and accommodation that he termed equilibration.

Piaget's stages of cognitive development

At the center of Piaget's theory is the principle that cognitive development occurs in a series of four distinct, universal stages, each characterized by increasingly sophisticated and abstract levels of thought. These stages always occur in the same order, and each builds on what was learned in the previous stage. During the first, or sensorimotor, stage (birth to 24 months), knowledge is gained primarily through sensory impressions and motor activity. Through these two modes of learning, experienced both separately and in combination, infants gradually learn to control their own bodies and objects in the external world. The ultimate task at this stage is to achieve a sense of object constancy, or permanence—the sense that objects go on existing even when we cannot see them. This developing concept can be seen in the child's keen enjoyment of games in which objects are repeatedly made to disappear and reappear.

The preoperational stage (ages two to six years) involves the manipulation of images and symbols. One object can represent another, as when a broom is turned into a "horsey" that can be ridden around the room, and a child's play expands to include "pretend" games. Language acquisition is yet another way of manipulating symbols. Key concepts involved in the logical organization of thoughts—such as causality, time, and perspective—are still absent, as is an awareness that substances retain the same volume even when shifted into containers of different sizes and shapes. The child's focus remains egocentric throughout both the preoperational and sensorimotor stages.

During the third, or concrete operational, stage (six or seven to 11 years of age), children can perform logical operations, but only in relation to concrete external objects rather than ideas. They can add, subtract, count, and measure, and they learn about the conservation of length, mass, area, weight, time, and volume. At this stage, children can sort items into categories, reverse the direction of their thinking, and think about two concepts, such as length and width, simultaneously. They also begin to lose their egocentric focus, becoming able to understand a situation from the viewpoint of another person.

The fourth, or formal operations, stage begins in early adolescence (age 11 or 12) with the development of the ability to think logically about abstractions, including speculations about what might happen in the future. Adolescents are capable of formulating and testing hypotheses, understanding causality, and dealing with abstract concepts like probability, ratio, proportion, and analogies. They become able to reason scientifically and speculate about philosophical issues. Abstract concepts and moral values become as important as concrete objects.

Modern views

In the decades since Piaget's theory of cognitive development became widely known, other researchers have contested some of its principles, claiming that children's progress through the four stages of development is more uneven and less consistent than Piaget believed. It has been found that children do not always reach the different stages at the age levels he specified, and that their entry into some of the stages is more gradual than was first thought. However, Piaget remains the most influential figure in modern child development research, and many of his ideas are still considered accurate, including the basic notion of qualitative shifts in children's thinking over time, the general trend toward greater logic and less egocentrism as they get older, the concepts of assimilation and accommodation, and the importance of active learning by questioning and exploring.

The most significant alternative to the work of Piaget has been the information-processing approach, which uses the computer as a model to provide new insight into how the human mind receives, stores, retrieves, and uses information. Researchers using information-processing theory to study cognitive development in children have focused on areas such as the gradual improvements in children's ability to take in information and focus selectively on certain parts of it and their increasing attention spans and capacity for memory storage. For example, they have found that the superior memory skills of older children are due in part to memorization strategies, such as repeating items in order to memorize them or dividing them into categories.

Today it is widely accepted that a child's intellectual ability is determined by a combination of heredity and environment. Thus, although a child's genetic inheritance is unchangeable, there are definite ways that parents can enhance their children's intellectual development through environmental factors. They can provide stimulating learning materials and experiences from an early age, reading to and talking with their children and helping them explore the world around them. As children mature, parents can both challenge and support the child's talents. Although a supportive environment in early childhood provides a clear advantage for a child, it is possible to make up for early losses in cognitive development if a supportive environment is provided at some later period, in contrast to early disruptions in physical development, which are often irreversible.