Page "Human evolution" Paragraph 8

The human species developed a much larger brain than that of other primates – typically 1, 330 cc in modern humans, over twice the size of that of a chimpanzee or gorilla.

The pattern of encephalization started with Homo habilis which at approximately 600 cc had a brain slightly larger than chimpanzees, and continued with Homo erectus ( 800-1100 cc ), and reached a maximum in Neanderthals with an average size of ( 1200-1900cc ), larger even than Homo sapiens.

The pattern of human postnatal brain growth differs from that of other apes ( heterochrony ), and allows for extended periods of social learning and language acquisition in juvenile humans.

However, the differences between the structure of human brains and those of other apes may be even more significant than differences in size.

The increase in volume over time has affected different areas within the brain unequally-the temporal lobes, which contain centers for language processing have increased disproportionately, as has the prefrontal cortex which has been related to complex decision making and moderating social behavior.

Encephalization has been tied to an increasing emphasis on meat in the diet, or with the development of cooking, and it has been proposed that intelligence increased as a response to an increased necessity for solving social problems as human society became more complex.