Evolution of human life history

The postnatal life cycle of the social mammals, including the nonhuman primates, has three basic stages of development: infant, juvenile, and adult. Human beings are unusual and add a childhood stage after infancy and an adolescence stage after the juvenile stage. The human pattern of life history in both brain and body growth entails a large investment of energy and time by older members of the social group toward infants and children. This is achieved via a new type of breeding strategy called biocultural reproduction. The evolution of human life history results in enhanced reproductive success for the individuals and our species.