Human Brain Evolution
Much of the allure of the neurosciences stems fromthe common conviction that there is something unusualabout the human brain and its behavioral capacities.Nevertheless, modern neuroscientists have paid ratherlittle attention to the study of brain evolution, and soour understanding of how the human brain differsfrom that of other animals is very rudimentary. In part,this neglect is due to a widely held belief that mammalianbrains are all essentially similar in their internalstructure and that species differ mainly in the size ofthe brain. This chapter reviews the modern evidenceconcerning brain evolution and shows that brain structure,far from being uniform across species, exhibitssome remarkable variations. Because the subject isvast, the discussion is necessarily selective. Thus, aftera brief review of evolutionary principles, this chapterdescribes the evolutionary history of three groupsof vertebrates that are of special interest to people:mammals, primates, and humans themselves. Themajor steps are outlined in the evolution of our large,complex, and extremely useful brains from the smaller,simpler brains of the first mammals, focusing on theneocortex, as this part of the brain has been studiedmost extensively. The neocortex is disproportionatelylarge in humans and is critically involved in mentalactivities and processes that are considered to be distinctlyhuman.[p. 1019]
EDITOR: Squire, Larry R.; Berg, Darwin; Bloom, Floyd E.; du Lac, Sascha; Ghosh, Anirvan; Spitzer, Nicholas
