Statistical assessment of the temporal and cultural relationship between the Lomekwian and Oldowan

Abstract

The temporal relationship between the Lomekwi 3 archaeological site and the Oldowan stone tool industry is not well explored. Lomekwi 3 dates to 3.3 million years ago (Ma), meaning the ‘Lomekwian’ as we currently understand it is 719 thousand years (Ka) older than the current oldest known Oldowan site, Ledi-Gararu. Here, we investigate the temporal relationship between Lomekwi 3 and early Oldowan occurrences using the ‘surprise test’, a statistical technique able to assess the temporal cohesion of cultural occurrences. It evaluates the null hypothesis that Lomekwi 3 was produced by the same cultural process responsible for the Oldowan, and does so by determining the temporal exceptionality of an outlying occurrence (i.e., Lomekwi 3) relative to a larger sample of earlier or later occurrences (in this case early Oldowan sites). Results indicate the null hypothesis cannot be rejected, suggesting Lomekwi 3 to potentially be from the same cultural process responsible for the Oldowan. This lack of temporal distinction means the former cannot reliably be inferred to be outside of the temporal range of the latter, increasing the feasibility of a cultural evolutionary relationship between Lomekwi 3 and the Oldowan and emphasising the need for a more widely evidenced technological distinction between the two. Additionally, we examine the impact of a less porous Oldowan record on these results by simulating the discovery of additional early Oldowan sites. The addition of five or more sites was required to guarantee a significant result. Thus, temporal evidence suggests Lomekwi 3 and the Oldowan should currently be considered part of the same cultural process (i.e., not to result from technological convergence), but this scenario could change through additional site discoveries.