There was probably a time when human culture was transmitted spontaneously from one generation to another. The young of the species cannot survive to maturity unless they assimilate some beliefs about the world, some attitudes toward it, and some skill in solving the practical problems it presents; and the only source from which they can derive this minimal wisdom is the culture of their elders. The tendency to imitate offers a ready-made mechanism for inheritance, and in primitive communities, where benign surroundings allowed a leisurely and spontaneous association with children or where a harsh environment spared no time from the effort to keep soul and body together, the education of the young must have proceeded without much thought or care. In societies that were a little more advanced, the need for instruction in tribal ceremonies and the apprenticeship of sons...