“If you had a yard as a child, you probably remember it with a startling intimacy. You knew that yard: every inch, every bush, each step on the tree you could climb, the whorls and knots in the branches, the bare dirt spots, the sandy gravel, the soft grass. It was deep, profound, intimate local knowledge. You intuitively knew what was happening around you at all times. Primitive man would have felt that way about a much larger stretch of ground, but it was still "his" territory. This very ability is really what allowed Homo sapiens to expand and succeed the way he did.”