Pub. date: 2005 | Online Pub. Date: September 15, 2007 | DOI: 10.4135/9781412950565 | Print ISBN: 9780761928201 | Online ISBN: 9781412950565| Publisher:SAGE Publications, Inc.About this encyclopedia
Human Brain, Evolution of
Paleoanthropological research in Eastern and Southern Africa has provided extensive fossil records documenting human evolution over the past 2 to 3 million years. The sites from Koobi Fora, Olduvai Gorge, Omo Sterkfontein, and Swartkrans have been studied (Johanson & White, 1979). Specimens from these sites are more primitive than homonid specimens found elsewhere. The volume of a human brain is measured by its cranial capacity and depends on several factors, for example, environment and body size. The average cranial capacity of Australopithecus , our ancient ancestors, was about 450 cc in the gracile species and 600 cc in the robust species. Members of the genus Homo H. habilis , who lived in East Africa about 2 million years ago, exhibited marked expansion of the brain with an average cranial capacity of about 750 cc. About 1.6 million years ago, it evolved into a larger, more robust, and larger-brained species known ...