Endocranial Volume and Brain Growth in Immature Neandertals

Microstructural studies have suggested that an extended period of growth was absent in representatives of Homo erectus, and that Neandertals reached adulthood significantly more rapidly than modern humans. In addition to general rate of growth, a prolonged postnatal period of brain development allows humans to develop complex cognitive and social skills. Conditions in brain growth similar to those observed in extant humans were not established in the first representatives of Homo erectus. To assess the degree of secondary altriciality reached by Neandertals, we examined the most complete skulls available for immature Neandertal specimens. The endocranial volumes were evaluated by using equations based on external cranial measurements. The proportional endocranial volumes (PEV) of these fossils were compared to the PEV of known age modern children from Western Europe and to a developmental series of Pan troglodytes. We present an estimation of the cranial capacity of Krapina 1. Although Neandertal children are close to the modern variation, the position of the youngest specimens in the upper range of variation led us to propose that Neandertals may have displayed a slightly more primitive pattern with respect to the speed of brain growth