It would be difficult to find another topic in anthropology that has played as important a role as innovation in structuring arguments concerning why and how human behavior changes. Certainly innovation was implicit in the 19th-century writings of ethnologists such as Edward Burnett Tylor and Lewis Henry Morgan, just as it was in the mid-20th-century work of Julian Steward and Leslie White. For Tylor and Morgan the appearance of cultural innovations was almost a preprogrammed process, which kicked in whenever a cultural group “needed” to ascend the ladder of sociocultural complexity. Adolf Bastian explained it this way: “the psychic unity of mankind constantly impelled societies to duplicate one another’s ideas” (Lowie 1937: 29). For Steward and White the process was less orthogenetic, with the source of innovation wrapped up in the kind of mechanisms a group needed to meet the challenges of its physical and social environment. Archaeological explanations of cultural change, too, have long centered around the introduction and spread of novelties. American culture historians of the 20th century routinely looked to diffusion and trade as a source of innovations, in the process usually adopting without comment the models of their anthropological colleagues as to how and why the innovations arose in the first place. This is the way that James Ford, a leading archaeologist of the mid-20th century, put it: “Archeologists have shown little interest in examining the philosophic bases of their studies. While utilizing the thesis that trait resemblances (in adjacent geographic regions) are evidence for contact, when faced with an unexplainable origin of a trait they have fallen back on independent invention theory” (Ford 1969:194). With the growing interest in Darwinian evolution that became noticeable in anthropology and archaeology after around 1980, researchers began to reconsider the role of innovation in the evolution of cultural systems. Importantly, modern evolutionary research in the social and behavioral sciences in general is being geared toward identifying innovation not only as a “thing” but also as a “process.” In that vein, a recent workshop at the Santa Fe Institute centered on innovation, building on the work of economist Joseph Schumpeter, who made the important distinction between invention—the creation and establishment of something new—and innovation—an invention that becomes economically successful and earns a profit (Erwin and Krakauer 2004: 117). This distinction had been made previously in biology—introduction and fixation of a novelty versus long-term success of a species—but not in the social sciences. There, the long-held belief that humans were somehow exempt from Darwinian processes such as natural selection ensured that the only brand of evolutionism discussed was of the unilinear Tylor-Morgan-White brand.