The Evolution of Human ChildhoodA unique growth phase and delayed maturity allow for extensive learning and complex culture

T b r he pattern of human growth from birth to adulthood is characterized by a prolonged period of infant dependency, an extended period of childhood and juvenile growth, and a rapid and large acceleration in growth velocity at adolescence that leads to physical and sexual maturation. This pattern is unusual for mammals in that most mammalian species progress from the infant nursing period to adulthood without any intervening stages. Compared with other mammals, nonhuman primates extend the infancy period. Many species of monkeys and apes have a phase of juvenile growth, defined as the time of independence from parental care after weaning and before sexual maturation. Only the human species has childhood as a step in the life cycle, and it is a step which is well defined from both a physiological and behavioral perspective. The purpose of this article is to take an evolutionary approach toward human development and show how childhood may be considered a unique characteristic of Homo sapiens. Only the human species has childhood as a step in the