Reconstructing Skills and Strategies of Hominins During the Early Acheulean: Behavioral Flexibility in Handaxe Production at Olduvai Gorge (Tanzania)

Abstract Technological strategies for biface manufacture adopted during the Acheulean represent a significant shift in the Lower Palaeolithic. The appearance of intentional bifacial shaping indicates the imposition of form on stone tools not seen previously. Despite this importance, there is considerable scope for research into hominin decision-making while factoring in the differential properties of varied raw materials. Here, we discuss the results of an experimental knapping program of Acheulean handaxes on Naibor Soit quartzites (NSQ), aiming at investigating technological strategies observed at the Lower Floor TK Site (TKLF), Olduvai Gorge, Tanzania. We examine the unique properties of the NSQ raw material and the challenges faced during knapping slabs at various stages of the handaxe reduction sequence. We explore how the selection and extraction of suitable slabs for handaxe manufacture and the impact of specific geological structures within this raw material determine the final artefact form. We note the effect this had on the need for careful choices in selecting suitable slabs at the raw material sources based on considerations of the properties of the slab, thickness, and width, amongst other factors. Functional requirements and the NSQ slabs’ properties influenced strategies adopted for handaxe façonnage and the final tool morphology. We discuss choices made by Acheulean toolmakers when they adopted freehand and bipolar knapping techniques. These decisions can be identified through the nature of the debitage generated and the organization of flake scars on handaxes. We suggest that Acheulean hominins displayed high skill levels and evolved knapping strategies. These strategies allowed them to adapt to the complex task of implementing specific shaping techniques on NSQ slabs. This provides one of the few experimental studies that directly explore the impact of the particular requirements of flaking quartzites during the Acheulean. This study contributes to understanding the diversity of strategies and behavioral flexibility exhibited by Acheulean hominins. Highlights • Experimental knapping of handaxes on Naibor Soit quartzite (NSQ) slabs, Olduvai Gorge, Tanzania. • Reproduction of the reduction sequence used for handaxe façonnage on slabs at the Acheulean level of Lower Occupation Floor in Thiongo Korongo site (TKLF). • Investigating decision-making at various stages of the handaxe reduction sequence. • Issues related to the NSQ, leading to breakage and steps adopted by the knapper to control for the same. • Inferences on Acheulean technological abilities based on experimental studies and knapping decisions at stages in the reduction sequence.