Were Acheulean Bifaces Deliberately Made Symmetrical? Archaeological and Experimental Evidence

Abstract

Acheulean bifaces dominate the archaeological record for 1.5 million years. The meaning behind the often symmetrical forms of these tools is the topic of considerable debate, with explanations ranging from effectiveness as a cutting tool to sexual display. Some, however, question whether the symmetry seen in many Acheulean bifaces is intentional at all, with suggestions that it is merely the result of a bias in hominin perception or an inevitable consequence of bifacial flaking. In this paper we address the issue of intention in biface symmetry. First, we use transmission chain experiments designed to track symmetry trends in the replication of biface outlines. Secondly, we use archaeological data to assess the symmetry of Acheulean bifaces from British, East African and Indian assemblages in relation to reduction intensity; the degree of bifaciality; and the symmetry of four Middle Palaeolithic bifacial core assemblages. Thirdly, we look at specific examples of the reduction sequences that produced symmetrical Acheulean cleavers at the sites of Olorgesailie CL1-1, Isinya, Chirki, Morgaon and Bhimbetka. All three lines of evidence support the notion that symmetry was a deliberately imposed property of Acheulean bifaces and not an epiphenomenon of hominin visual perception or bifacial technology.

Aesthetic sense and social cognition: a story from the Early Stone Age

“…27 Tehrani and Riede (2008, p. 318). Indeed there is evidence of copying errors in the archaeological record, adding support to the idea that the reproduction of tool-making techniques was intrinsically difficult; see Lycett et al (2016) and Shipton et al (2019).…”

How does thinking relate to tool making?

“…The debate over the so-called ‘handaxe enigma’ has been focusing especially on whether the symmetry of Acheulean bifaces is intentional (a conscious decision made by the knapper) or a mere consequence of bifacial flaking (e.g. Shipton & Clarkson, 2015a, 2015b; Shipton et al, 2019; Hodgson, 2015; Kohn & Mithen, 1999; McPherron, 2000; Nowell & Lee Chang, 2009). For some researchers, lithic raw material qualities and mechanical constraints were the main determining factors in stone tool morphology.…”

“…There is a wide range of skills that need to be learned and practised in the relevant contexts of situated action. Still, within this broad spectrum of skill and expertise, the knapper must be able to sense the qualities of the stone, and predict the consequence of a strike given, as well as organise various functional parameters and gestural variables simultaneously (Chazan, 2015; Moore & Perston, 2016; Nonaka et al, 2010; Roux & Bril, 2005a, 2005b; Roux et al, 1995; Shea, 2015; Shipton et al, 2019; Stout et al, 2014; Hutchence & Debackere, 2018). The skills and bodily techniques needed to control the shape of a flake take years of practice.…”

Pilot study comparing the effects of thinning processes on the cross‐sectional morphologies of Early and Late Acheulian handaxes

“…The morphology of handaxes has been a critical subject of debate in Early Stone Age archaeology (Stout 2011;Hodgson 2015;McNabb and Cole 2015;Shipton 2016;Shipton et al 2019;García-Medrano et al 2020). The consistency of handaxe forms found throughout Africa, Asia and Europe has highlighted specific 'rule-sets' underlying their manufacture, which has provided an insight into the intentionality and technical skill of Acheulian toolmakers (Bordes 1961;Roe 1968;Crompton and Gowlett 1993;Gowlett 2006;Stout 2011;García-Medrano et al 2014;Kuman et al 2014;Shipton 2016).…”

“…While thinning processes potentially distinguish Late Acheulian handaxes from earlier forms, studies investigating their effect on morphological variation are rare (García-Medrano et al 2019). The analysis of handaxe shape has been predominantly focused on issues of symmetry and shape variation, the latter referring to differences in handaxe forms (i.e., pointed versus ovate) (Iovita and McPherron 2011;Shipton and Clarkson 2015;Shipton et al 2019). However, relating these factors to specific manufacturing procedures remains challenging.…”