Critical period in child development Critical period in child development Development is the pattern of change that begins at conception and continues through the life cycle. For the purposes of organization and understanding, development is commonly described in terms of periods. Approximate age ranges are placed on the periods to provide a general idea of when a period first appears and when it ends. The prenatal period is the time from conception to birth. Infancy is the developmental period that extends from birth to eighteen to twenty-four months.
Infancy is a time of extreme dependence on adults.
Many psychological activities are just beginning- language, symbolic thought, sensorimotor coordination, and social learning, for example. First grade typically marks the end of this period. Children master the fundamental skills of reading, writing, and arithmetic, and they are formally exposed to the larger world and its culture. Achievement becomes a more central theme of the child s world, and self-control increases. Adolescence is the developmental period of transition from childhood to early adulthood, entered approximately at ten to twelve years of age and ending between eighteen and twenty years of age.