Processual archaeology formerly the New Archaeology is a form of archaeological theory which arguably had its genesis in 1958 with Willey and Phillips' work, Method and Theory in American Archeology in which the pair stated that "American archaeology is anthropology or it is nothing" Willey and Phillips, 1958:2, a rephrasing of Frederic William Maitland's comment that "my own belief is that by and by anthropology will have the choice between being history and being nothing."
During the nineteenth century, archaeology expanded its purview to include other civilizations and older periods of human habitation. Archaeological investigation became central to the development of theories of cultural evolution, particularly to theories of the necessary stages of societal development. This idea implied that the goals of archaeology were, in fact, the goals of anthropology, which were to answer questions about humans and human society.

This was a critique of the former period in archaeology, the Culture-Historical phase in which archaeologists thought that any information which artifacts contained about past people and past ways of life was lost once the items became included in the archaeological record. All they felt could be done was to catalogue, describe, and create timelines based on the artifacts. The new methodological approaches of the processual research paradigm include logical positivism (the idea that all aspects of culture are accessible through the material record), the use of quantitative data, and the hypothetico-deductive model.