Since the end of the 19th century, biologists have paid particular attention to the alteration of growth processes in human evolution. The theoretical models of neoteny and hypermorphosis proved too simplistic to explain human anatomical evolution. Nonetheless, the ontogenic development of our species presents some highly original features. Compared to our closest primate relatives, human growth is characterized by its prolonged duration and the presence of an accelerated growth phase during adolescence.
Some of these adaptive changes are linked to the presence of a large, energy-intensive brain, particularly in early childhood. The extension of brain volumetric growth after birth and the introduction of early weaning have enabled the human species to respond to the anatomical and energetic constraints resulting from its high level of encephalization. Thanks to the sharing of food within social and family networks, women can simultaneously raise several children of different ages and transfer some of the energetic burden this represents to other adults.
Examination of different fossil hominin groups shows that we cannot simply oppose a "human" development model to a "great ape" model. In fact, each group considered seems to have achieved a different growth pattern that responds to particular anatomical and behavioral conditions. It is apparently only relatively recently in the course of human evolution, and probably only within our own species, Homo sapiens, that a growth pattern comparable to that observed in today's populations was established.
