We define diversity in core reduction systems as the degree of deviation from the most efficient means to proceed from the start to the end product exhibited in a given core reduction system. Because lithic core reduction systems are often characterized along a continuum of high or low degree of diversity, some archaeologists have suggested that assemblage diversity is linked to raw material availability and quality. In this paper we provide a model that predicts when humans would favor less systematic core reduction techniques as opposed to those that are more systematic. The model incorporates three factors influencing diversity in core reduction techniques: raw material availability, raw material quality, and the ratio of producers to consumers. We provide the model and then estimate where several case examples from different archaeological contexts fit within the expectations. This allows us to generate hypotheses about the relationship of producers and consumers who manufactured the assemblages.
The process of lithic core reduction is often described as systematic (nearly uniform) or unsystematic (highly variable) (Bleed 2001; Brantingham et al. 2000; Root 1997). For example, some core reduction systems represent human interaction with raw materials that are much more prone to knapping error and failure rates, whereas others appear to follow very specific chains (for an example of each, see Bleed 1996, 101–2).