Developmental psychology, also known as human development, is the scientific study of systematic psychological changes, emotional changes, and perception changes that occur in human beings over the course of their life span. Originally concerned with infants and children, the field has expanded to include adolescence, adult development, aging, and the entire life span. This field examines change across a broad range of topics including motor skillsand other psycho-physiological processes; cognitive development involving areas such as problem solving, moral understanding, and conceptual understanding; language acquisition; social, personality, and emotional development; and self-concept and identity formation. 3 major contexts to consider when analysing child psychology are: social context, cultural context, and socioeconomic context. Developmental psychology includes issues such as the extent to which development occurs through the gradual accumulation of knowledge versus stage-like development, or the extent to which children are born with innate mental structures versus learning through experience. Many researchers are interested in the interaction between personal characteristics, the individual's behavior, and environmental factors including social context, and their impact on development; others take a more narrowly-focused approach.
Developmental psychology informs several applied fields, including: educational psychology, child psychopathology, and forensic developmental psychology. Developmental psychology complements several other basic research fields in psychology including social psychology, cognitive psychology,ecological psychology, and comparative psychology.
Many theoretical perspectives attempt to explain development; among the most prominent are: Jean Piaget's Stage Theory, Lev Vygotsky's Social constructivism (and its heirs, the Cultural Theory of Development of Michael Cole, and the Ecological Systems Theory of Urie Bronfenbrenner), Albert Bandura's Social learning theory, and the information processing framework employed by cognitive psychology.
To a lesser extent, historical theories continue to provide a basis for additional research. Among them are Erik Erikson's eight stages of psychosocial development and John B. Watson's and B.F. Skinner's behaviorism. For more on behaviorism's role see Behavior analysis of child development).
Many other theories are prominent for their contributions to particular aspects of development. For example, attachment theory describes kinds of interpersonal relationships and Lawrence Kohlbergdescribes stages in moral reasoning.
Ecological Systems Theory
Main article: Ecological Systems Theory
Also called "Development in Context" or "Human Ecology" theory, Ecological Systems Theory, originally formulated by Urie Bronfenbrenner specifies four types of nested environmental systems, with bi-directional influences within and between the systems. The four systems are microsystem, mesosystem, exosystem, and macrosystem. Each system contains roles, norms and rules that can powerfully shape development. Since its publication in 1979, Bronfenbrenner's major statement of this theory, The Ecology of Human Development has had widespread influence on the way psychologists and others approach the study of human beings and their environments. As a result of this conceptualization of development, these environments—from the family to economic and political structures—have come to be viewed as part of the life course from childhood through adulthood.
Main article: Attachment theory
Attachment theory, originally developed by John Bowlby, focuses on open, intimate, emotionally meaningful relationships. Attachment is described as a biological system or powerful survival impulse that evolved to ensure the survival of the infant. A child who is threatened or stressed will move toward caregivers who create a sense of physical, emotional and psychological safety for the individual. Attachment feeds on body contact and familiarity. Later Mary Ainsworth developed the Strange Situation Protocol and the concept of the secure base. See also the critique by developmental psychology pioneer Jerome Kagan.
Unfortunately, there are situations that inhibit a child from forming attachments. Some babies are raised without the stimulation and attention of a regular caregiver, or locked away under conditions of abuse or extreme neglect. The possible short-term effects of this deprivation are anger, despair, detachment, and temporary delay in intellectual development. Long-term effects include increased aggression, clinging behavior, detachment, psychosomatic disorders, and an increased risk of depression as an adult.
Main article: Nature versus nurture
A significant issue in developmental psychology is the relationship between innateness and environmental influence in regard to any particular aspect of development. This is often referred to as "nature versus nurture" or nativism versus empiricism. A nativist account of development would argue that the processes in question are innate, that is, they are specified by the organism's genes. An empiricist perspective would argue that those processes are acquired in interaction with the environment. Today developmental psychologists rarely take such extreme positions with regard to most aspects of development; rather they investigate, among many other things, the relationship between innate and environmental influences. One of the ways in which this relationship has been explored in recent years is through the emerging field of evolutionary developmental psychology.
One area where this innateness debate has been prominently portrayed is in research on language acquisition. A major question in this area is whether or not certain properties of human language are specified genetically or can be acquired through learning. The empiricist position on the issue of language acquisition suggests that the language input provides the necessary information required for learning the structure of language and that infants acquire language through a process of statistical learning. From this perspective, language can be acquired via general learning methods that also apply to other aspects of development, such as perceptual learning. The nativist position argues that the input from language is too impoverished for infants and children to acquire the structure of language. Linguist Noam Chomsky asserts that, evidenced by the lack of sufficient information in the language input, there is a universal grammar that applies to all human languages and is pre-specified. This has led to the idea that there is a special cognitive module suited for learning language, often called the language acquisition device. Chomsky's critique of the behaviorist model of language acquisition is regarded by many as a key turning point in the decline in the prominence of the theory of behaviorism generally. But Skinner's conception of "Verbal Behavior" has not died, perhaps in part because it has generated successful practical applications.