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As Darwin and Wallace neatly surmised, organic evolution results from a selection process that acts to preserve traits better suited for a given habitat. And there is no better example of its potent influence than the hominin brain and mind. Why do humans have such large and complex brains? As a rule, larger brains are energy costly so we can assume that our encephalized brain evolved to meet environmental demands, and if so, clues should exist in the context of the problems it evolved to solve. As the control center for human activity, the brain directs all body functions—from our extraordinary sensorimotor skills to lots of mind-related business. It houses both a 'social self" with a complex linguistic-based communication system to move ideas from one mind to another and an "individual self," a rare character in the animal world that lends itself to a personal identity distinct from other conspecifics and to the taking of the role of others. The elusive social mind also has the novel capacity to engage in two distinctive types of sociality—the ability to form tight-knit kinship bonds or strong ties, a trait shared with all social mammals, and the ability to form loose-knit friendship bonds or weak-ties, a rare trait in the animal world but essential for the creation of large-scale societies with millions of individuals. What compelling demands in our ultimate history fostered such splendid cognitive traits?The objective of this chapter is to review and interpret what is known about the evolution of the hominin brain with a focus on what was created. The human brain with its suite of novelties was not created by random mutations, a single adaptive package, or a concurrent sequence of events. Rather it was assembled in a variegated mosaic pattern over a span of nearly 60 million years of primate evolution. And, while the jury is still out, the bulk of the evidence on the hominin brain points to three key events that shaped the cognitive software that lies beneath its convoluted surface—the expansion of the primate neocortex and the shift to visual dominance, the selective "cheery picking" of the swinging Miocene apes, and the Pleistocene shift of Homo erectus to an open-country niche.

DOI: 10.1007/978-94-007-4473-8_18

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