Sex, Symmetry and Silliness in the Bifacial World
Hayden, Brian, Villeneuve, Suzanne, Antiquity
After 10 years of pursuing sexy handaxes it is probably time to put these coquettish creatures to bed. Readers wishing to continue the debate are courteously directed to our Project Gallery
As lithic technologists, we were at first amused by Kohn and Mithen's (1999) arguments to the effect that handaxes developed in order to enhance sexual selection among early hominins. However, contributors to Antiquity continue to take their suggestions seriously and even to extend them to new heights (Machin 2008; Mithen 2008; Hodgson 2009). We would like to bring the issues back down to the ground, and discuss the practical and technological aspects of biface manufacture which these authors do not seem to have appreciated. This is perhaps not surprising since none of the authors appear to have much experience in manufacturing stone tools. We do agree with them that a socially-oriented analysis of stone tools is desirable, but this must be founded on a solid understanding of lithic technology.
Kohn and Mithen's (1999: 520) original argument, as with subsequent versions published in Antiquity, is based on the fundamental assertion that 'in the majority of artefacts a specific symmetrical form was imposed ... an imposed symmetry beyond functional requirements.' This assertion was supported by a study of the effectiveness of symmetrical versus asymmetrical handaxe performance in butchering (Machin et al. 2006). Mithen (2008: 766-9) continues to claim that his sexual selection explanation is the only theory that can account for the features typical of handaxes. One hesitates to accept these claims at face value when also confronted with highly questionable assertions to the effect that bones were used as billets and handaxes were used for chopping up vegetables. The same fundamental premise has been uncritically adopted by subsequent commentators who propose variously that consistency of form in handaxes was the product of natural selection (for unstated reasons--Machin 2008: 763); or that symmetry evolved among animals in general as a means of identifying things in the world and that handaxe symmetry evolved to create reassurance that an unspecified critical aspect of the human perceptual system was working appropriately (Hodgson 2009). Machin subsequently presented cogent arguments from a Darwinian viewpoint as to why handaxes would make poor candidates for use in sexual selection.
What Kohn and Mithen fail to acknowledge is that there is a practical technological logic behind the symmetry and other characteristics of bifaces. This does not appear to be very evident from cognitive evolutionary perspectives. What we suggest is that analysing handaxe symmetry from a design theory viewpoint can be much more insightful. Design theory involves: 1) the identification of a specific problem to be solved; 2) the identification of relevant constraints (typically factors such as material costs and availability, performance characteristics, required skill, processing volumes, time availability, existing technology, mobility and transport limitations, and available labour); and 3) identifying the trade-offs in advantages and disadvantages of certain constraints (such as material procurement costs) against the advantages and disadvantages in other constraints (such as effectiveness). These factors are then used to develop a suite of design solutions (Pye 1964, 1968; Horsfall 1987; Hayden 1998; Hayden et al. 2000).
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In order to demonstrate the potential utility of design theory, the issue of handaxe symmetry can be considered in the broader context of general trends throughout the Stone Age toward greater economy in the use of lithic material employed in high-consumption activities. Greater material economy is manifested by changes in core reduction techniques and resharpening techniques; and these, in turn, arguably reflect changes in major design constraints. Oldowan choppers/cores, for example, produce a minimal number of flakes or resharpenings per kilogram of tool stone due to the hard hammer techniques employed. …