Developmental psychology is the scientific study of age related changes in behavior across the life span. This field examines change across a broad range of topics including: motor skills, problem solving abilities, conceptual understanding, acquisition of language, moral understanding, and identity formation.
Questions addressed by developmental psychologists include the following. Are children qualitatively different from adults or do they simply lack the experience that adults draw upon? Does development occur through the gradual accumulation of knowledge or through shifts from one stage of thinking to another? Are children born with innate knowledge or do they figure things out through experience? Is development driven by the social context or by something inside each child?
Many theoretical perspectives attempt to explain development, among the most prominent are: Jean Piaget's Stage Theory, Lev Vygotsky's Social Contextualism, and the information processing framework. Historical theories continue to provide a basis for additional research, among them are Erik Erikson’s life-span stage theory, John Watson’s and B. F. Skinner’s Behaviorism, and a set of nested levels of context proposed by Urie Bronfenbrenner. Many other theories are prominent for their contributions to particular aspects of development. For example, Attachment theory describes kinds of interpersonal relationships and Lawrence Kohlberg describes stages in moral reasoning.
The term "child" is also a counterpart of parent: adults are the children of their parents despite their maturation beyond infancy; for example "Benjamin, aged 46, is the child of Tobias, aged 73".
Child development is the study or examination of processes and mechanisms that operate during the physical and mental development of an infant into an adult.
While there are problems with such early "streaming", child murder, child abandonment, military use of children and other major social ills are thought to be reduced by a human development approach – as there is a high value assigned to children by the state.