The Skinny on Brains: Size Matters.

This article is the second of two that addresses the development of the human brain. Last month's article, "The Evolution of Human Capabilities and Abilities," focused on neurons, the basic information-processing units of the nervous system. This month's article examines the evolution of the neocortex, a part of the cerebral cortex concerned with sight and hearing in mammals, regarded as the most developed part of the cortex .