Modeling Use-Life Distributions in Archaeology Using New Guinea Wola Ethnographic Data

Assemblages are composed of proportions of artifacts by category. Use life affects the formation and therefore the size and composition of assemblages. Use life is to assemblage formation as lifespan is to demography, and demographers know that a population's mean lifespan is no more important than the distribution of values around that mean. When considered at all, use life typically is expressed as a mean value. But use-life's distribution—variation around the mean—affects assemblage composition independently of the mean. Distribution is neglected because its effects are not appreciated and seem difficult to measure. To improve understanding of assemblage formation, we study use-life distribution in New Guinea Wola ethnographic artifacts, using cumulative survivorship and the two-parameter Weibull model. Then we propose estimates of use-life distribution in Paleoindian stone tools. Knowing use-life distribution as well as mean, we know better how assemblages formed and improve our understanding of the archaeological record.