Australopithecine Endocasts, Brain Evolution in the Hominoidea, and a Model of Hominid Evolution

Abstract

It is important that the cortex of the australopithecine brain was apparently organized toward the modern human condition; knowing the precise amount of increase in relative size of temporal or parietal cortex would not add anything essential to understanding of the fact. The chapter describes some concrete evidence for brain reorganization resulting from studies on the early hominid endocasts from South Africa. It also describes an admittedly speculative model of early hominid evolution. There are three ways by which one may approach the evolution of the human brain: the study of the only empirical evidence of brain evolution, paleoneurology, or the study of endocasts; neurological study of an extant comparative series; study of neurological parameters and behavior, which can include neurophysiology, neurochemistry, inbred strains, and neurological genetics. Data on the non-neural contributions to cranial capacity are needed for all hominoids to provide better estimates of neural contents.