Archaeology of the origins: emergence and evolution of the first human technologies – ARCHOR

ARCHOR relied on data from the archaeological excavation of the LOM3 site by the Mission Préhistorique au Kenya. The lithic material collected during the excavation was the subject of a technological analysis by various specialists in order to be studied as finely as possible. In order to understand how they were made, the stone artifacts collected were subjected to a technological analysis and were systematically replicated. Some pieces were also selected for study by a traceologist who examined any traces of use of their cutting edges. Lithic material bearing visible traces of percussion has been studied by a specialist in percussive tools. The microscopic and macroscopic analysis of the surfaces of the objects made it possible to define the way in which they had been used. A protocol for analyzing the 3D movement of the arm and forearm during the knapping process made it possible to evaluate the motor skills involved in the size of the tools and in particular those related to the hand. The study of the external and internal morphological characters (Ct-Scan) of hominin bones discovered near LOM3 as well as their taxonomic determination was conducted in an evolutionary perspective. Geological mapping of sediments, geochemical analyzes of paleosols and fossil remains, and paleoecological diagrams made it possible to determine the palaeoenvironmental and palaeoecological contexts in which the hominins of West Turkana evolved between 3.3 and 1.7 Ma.

Evolutionists have long assumed that the first stone tools were made 2.5 Ma ago by the genus Homo and that this technological development was directly related to climate change and the spread of savanna grasslands. Our results show, on the contrary, that another kind of hominins, probably an older form of Australopithecus (or Kenyanthropus) then evolving in East Africa already had, 3.3 Ma, cognitive abilities and sufficient motor skills for the controlled production of the LOM3 flakes. These were produced by a unipolar and unifacial single exploitation of cores from large selected blocks of basalt and phonolite. Two simple percussion techniques have been identified for knapping at LOM3: the bipolar percussion technique and the passive hammer technique. It remains to explore whether these techniques can derive from pre-existing and pre-3.3 Ma hammering activities.

ARCHOR has undeniably allowed us to revisit some major questions concerning the processes of emergence of our humanity and in this, we consider our ANR a success. ARCHOR helped to identify new questions but also to think about new methodologies that will effectively answer these questions, such as the need to better understand the evolution of complex cognitive functions such as tool making and foraging, and the functional analysis of the upper limbs and the hand. This is proposed in the framework of the new project ANR HOMTECH (dir S. Prat) which will start in March 2018 and involve some of the researchers involved in ARCHOR.

Our results have been widely promoted by ARCHOR members through professional symposiums and conferences, radio programs, newspaper. In addition to the scientific publication of the original article on Lomekwi 3 in Nature (cover in May 2015), our work has been highlighted in several special issues of magazines (Scientific American, Dossier Pour La Science) and articles of popular science (La Recherche, Pour La Science, Le Monde, etc). We also presented our research during radio programs (France Culture, NPR, France Inter, etc.). The quality of ARCHOR's work has been recognized through prestigious awards: four national or international awards (La Recherche Prize 2016, Vanity Fair Prize 2016, Shanghai Prize 2015, Stone Age Institute Award 2015 ). The impact and influence of our research in France and on the international scene is also reflected in more than 600 citations referring to our work in the media, 366 million media views on the internet. As part of the 10th anniversary of the ANR, our ARCHOR project has been chosen as one of the emblematic projects supported by the ANR for the last 10 years. Our work was particularly highlighted: 1) at the presentation of the casts of our tools by the President of Kenya at the Musée de l'Homme (6 April 2016); 2) during an anniversary day at the National Museum of Natural History (December 15, 2016) during which T. Mandon, Secretary of State for Higher Education and Research, was present; 3) with a mini exhibition presenting ARCHOR (featured on the ANR website). ARCHOR's scientific retrieval symposium allowed ARCHOR members to present and highlight their results in the Jean Rouch auditorium at the Musée de l'Homme in Paris (June 2017).

ARCHOR project falls within "Axe 1" of the ANR CULT. This project seeks to reconstruct the genesis of hominin technology as far back as 3 Ma and beyond. This multidisciplinary project will use the extremely rich field data collected by the West Turkana Archaeological Project in Northern Kenya, including the recent discovery (2011) of a stone tool assemblage securely dated at 3.1 Ma (LOM3), which thus represents the oldest archaeological site ever found yet. The goal is to study early hominids cognitive competence and motor skill exactly at the time of the emergence and the first evolutionary steps of a new and unique behaviour among primates: the making of stone tools. In our field of research, this behaviour developed among fossil hominids for which we cannot refer to any living example. The approach for studying the mind of these modern humans ancestors necessarily goes through a technological analysis of their lithic production, using the chaîne opératoire concept as a tool for analysis. We will also try to define what have been the environmental and paleoanthropological conditions which have favored the emergence of such a new behaviour, more than 3 Ma ago in the Turkana Basin. Thus, beyond its first goal which is to elucidate the technological steps which have led some hominids to specific evolution paths, it also contributes to illustrate the impact of global climatic changes on human evolution and to demonstrate the possible ways hominids have chosen to answer the environmental changes. As LOM3 marks the beginning of the archaeological record, some most fundamental questions must be asked anew. How, when, and why did stone tool manufacture and use originate? Did the earliest stone knapping develop naturally from pre-existing bashing behaviors or did it develop more punctually and directly to flaking for cutting edges? What were the first stone tools used for? Which species were the first stone tool makers? Over the last 15 years, new discoveries and studies have revealed unexpected hominin diversity and the complexity of their evolutionary history, during which different species coexisted at the same time in the same regions. In this context, deciphering the phylogenetic relationships between the various species that existed between 4 and 1.5 Ma, as well as assessing the mode and tempo of the emergence of the genus Homo, is challenging. How did biology, culture and environment interact? Which role did these factors and their interactions play in hominin evolutionary history? The emergence of manipulative skills is also still debated and identifying "When stone tool-making, human-like precision grip capabilities emerged" is crucial to the understanding of origins of technology and hominisation processes and one of the ARCHOR goals. The search for the emergence and evolution of the first techno-cultural assemblages and the conditions of this emergence is shared by several teams working in different parts of the world, but essentially within the Great Rift Valley in Eastern Africa. However no where else than in West Turkana there is an archaeological record having the following remarkable advantages: (1) it bears the oldest site ever found and the oldest Acheulean site (dated at 1.76 Ma); these two sites will be the terminus ante and post quem of ARCHOR project studies; (2) a large number of sites are distributed all along a sequence ranging from more than 3 Ma to 0.7 Ma; it garantees a thorough diachronical study, although in this project we will limit our time period study to its oldest part, the Oldowan; (3) it bears several Early Oldowan sites among the world oldest (at 2.3 Ma) and a large number of Oldowan sites (1.8 Ma), which guarantees a good synchronic perspective. We thus do think we have the best securely dated data record one can expect for the research domain we want to further explore.