The novelty of the processualist perspective lay in its rigorous approach to building theory with the goal of explaining why events occurred as they did. Though processual archaeology was, a fairly big tent, its basic premises are materialist, etic, and generalizing, and include an emphasis on structure over agency. In line with materialist thought, processualists argued that human behavior in all times and places functions to promote the physical survival of a culture’s members. British archaeologist David Clarke was among the most theoretically sophisticated of the processual archaeologists working in the 1960s and 1970s. Processualist views of systems theory tended to emphasize unidirectional causation with technological/demographic/ecological variables determining the form of social relations and shared beliefs in a culture. Kent Flannery was in the vanguard of those researchers who established the foundations of processualism. Processualists recognized that people often have different roles to play in adapting their cultures to the environment, roles enacted in different places spread across the landscape.