The various aspects of child development encompass physical growth, emotional and psychological changes, and social adjustments. A great many determinants influence patterns of development and change.
On the average, a newborn baby weighs 3.4 kg (7.5 lb) and is 53 cm (21 in) long, with the head disproportionately larger than the lower part of the body. As the child grows, increments in height are greatest from birth to three years; thereafter they are relatively constant until adolescence. The growth spurt at adolescence is far less than during infancy. Weight increments are also large during the first three years but are equally large during adolescence. Research shows that growth rates are influenced by the health of the child. Rates of development decelerate during illness; after an illness is cured, however, growth rates accelerate until children attain their appropriate height and weight.
Dramatic changes occur in motor skills from birth through the first two years. At birth infants are capable of extensive uncoordinated movements. One feature of the early motor behavior of infants is the large number of reflex-like actions. These actions appear for a short time after birth and then disappear. For example, when the palm of the hand is stroked lightly the fingers involuntarily close, forming a fist; this is called the palmar reflex. From these early movements, distinct sequential patterns of motor development occur. Walking, which occurs on the average between 13 and 15 months, emerges from a sequence of 14 earlier stages. Research shows that the rate of acquisition of motor skills is innately determined and that the acquisition of these skills is not influenced by practice. Severe restrictions on motor activities, however, will alter both the pattern and rate of development. After basic motor skills are acquired, children learn to integrate their movements with perceptual skills, especially spatial perception. This process is critical for the achievement of eye-hand coordination and for the higher-level skills required for many sports activities.
The ability to communicate and to understand language is a major achievement of human beings. An amazing feature of language development is the speed with which it is acquired: The first word is spoken at about 12 months; by two years of age most children have vocabularies of about 270 words, and this increases to 2600 words at the age of six. It is almost impossible to determine the number of sentence constructions that can be generated within a single language. Children, however, use syntactically correct sentences by the age of three and highly complex constructions by the age of five. This extraordinary phenomenon cannot be explained by means of simple learning theory. Today theorists are concerned with the relationship between cognitive growth and language. It is now assumed that language reflects children’s concepts and develops as their concepts expand.
Theories of personality are attempts to describe how people behave in satisfying their physical and psychological needs. An inability to satisfy such needs creates a personal conflict. Personality formation is viewed as the process by which children learn how to avoid conflict when possible and how to cope with conflict when it inevitably occurs. Overly restrictive or overly permissive parents limit their children’s options in avoiding and coping with conflict. A normal response to overwhelming conflict is to revert to a defense mechanism such as rationalization—the denial that one ever wanted a specific objective, for example. Although everyone uses defense mechanisms at some time, they should not become a person’s sole means of coping with conflict. A child with a balanced, integrated personality feels accepted and loved and has been allowed to learn a number of appropriate coping mechanisms.
Intelligence may be defined as the ability to manipulate abstract verbal concepts effectively. This definition is reflected in the types of questions asked on intelligence tests for children. Two well-known tests—the Stanford-Binet and the Wechsler Intelligence Scale for Children, Revised—are used to index children’s mental growth and to predict learning performances. Because school learning seems to depend on the ability to reason verbally, the content of intelligence tests seems appropriate. Some relationship does indeed exist between intelligence-test performance and school achievement. Predictions based on tests are imperfect, however, because intelligence tests do not measure motivation and because knowledge about the skills needed for school learning is incomplete. In addition, intelligence tests are sometimes inappropriate when used with minority children, who may not understand or respond appropriately to certain items because of language difficulties or cultural differences. Thus, test scores must be interpreted with great care.
The attitudes, values, and behaviors of parents toward their children clearly influence patterns of development. Likewise, children’s characteristics influence parental attitudes and behaviors; handicapped children, for example, require more attention and cause more parental anxiety than do normal children. Extensive studies have established that parental behaviors toward children vary widely, ranging from restrictiveness to permissiveness, warmth to hostility, and anxious involvement to calm detachment. These variations in attitudes produce different patterns in family relationships.
Social relationships among infants involve mutual interest without interaction. This relationship is called parallel play. Beginning with the preschool years, peer-group relationships become increasingly sophisticated social systems influencing children’s values and behaviors. The transition to the adult social world is aided by the organization of peer groups with a leader, members with varying strengths and weaknesses, and a recognition of the need for cooperative behavior. Peer-group conformity reaches a peak when children are about 12 years of age. Conformity never disappears, but its manifestations among adults are less obvious. The members of peer groups change with age. Preadolescent groups are homogeneous; that is, members are usually of the same sex and come from the same neighborhood. Among older children, social relationships are based on shared interests and values. Within a given group, the popular children tend to be more intelligent, higher achievers, and socially and emotionally more mature.
Much current work involves identifying the cognitive components (such as memory and attention span) used in problem-solving activities. Researchers also are trying to identify the processes that occur in the transition from one level of thought to the next. Another area of investigation is the cognitive components in reading and arithmetic. It is hoped that this research will lead to improved methods of teaching academic skills and more effective remedial teaching.