Use life and curation in New Guinea experimental used flakes

In 1983, Sillitoe timed New Guinea Wola men as they used chert flakes in customary tasks. We use the resulting data to distinguish the familiar but often conflated concepts of use life and curation, defining curation as the ratio of realized to maximum utility. We compile distributions of time-to-discard, analogous to mortality profiles in demography and zooarchaeology and failure distributions in engineering, and propose a quantitative curation measure, the Gompertz-Makeham b parameter, to characterize them. We compare this curation measure to use-life distributions. Despite use life measured only in minutes, curation varies independently of use life in different tool distributions. Some tools were well curated despite brief use. Thus, use-life can be short when curation is high; the quantities are independent. We discuss the implications of the ability to measure, not just subjectively judge, curation.