In Landscape of the Mind, John F. Hoffecker explores the origin and growth of the human mind, drawing on archaeology, history, and the fossil record. He suggests that, as an indirect result of bipedal locomotion, early humans developed a feedback relationship among their hands, brains, and tools that evolved into the capacity to externalize thoughts in the form of shaped stone objects. When anatomically modern humans evolved a parallel capacity to externalize thoughts as symbolic language, individual brains within social groups became integrated into a "neocortical Internet," or...