Processual archaeology developed earlier than evolutionary archaeology, but with the same goal of making archaeology more scientific. Even though it was in part a reaction against culture history, in practice the two were sometimes merged by describing the cultural systems of various culture periods. Most of its practitioners would also use some evolutionary schemes for explanation, whether it was progressive evolution or a less value-laden version. In contrast to evolutionary archaeologists, they saw evolution acting upon the cultural systems, which they reconstructed (though practitioners would not generally admit to “reconstruction” on their part), rather than artefact assemblages. Change was often seen in terms of the collapse of one system and the emergence of a new one, similar to the dominant view in ecology at the time.
While the processes of change were studied, in practice, processual archaeology tended to view cultural systems in nearly static terms. The relationships within such a system were studied through a host of specialists. We have processual archaeology to thank for the increased use of faunal, botanical, petrographic and statistical analysis, among a host of other specialised approaches. The aim was to combine these studies to describe the overall cultural system. In practice, also partly due to the academic pressure to produce articles, the various specialist studies are often published separately and are not integrated. Processual archaeology tends to disregard events and human intentionality, and to view human life in mechanistic terms. While it may be possible to analyse ancient lifeways, they would be seen in wholly functional terms. Because many archaeologists followed the notion of universal laws, the historically particular situation was often not addressed. History and culture were seen as distinct. These presuppositions have to be taken into account when trying to use archaeological data interpreted within this framework for writing history.