On Identifying Stone Tool Production Techniques: An Experimental and Statistical Assessment of Pressure Versus Soft Hammer Percussion Flake Form

Abstract

Identifying stone tool production techniques in the archaeological record can inform on prehistoric economy, time budgets, shared cultural practices, and the spatiotemporal occurrence of technological innovations and adaptations. The pressure flaking technique is one such innovation that appears on every continent Homo sapiens colonized. Pressure flaking has long been associated with the ability of flintknappers to produce small, regularly shaped flakes that were used to maintain particular edge shapes and resharpen dull tool edges with minimal loss of raw material. Despite the importance of pressure flaking, a method for supporting the identification of pressure flakes in the archaeological record is lacking. Here, we present a stone tool replication experiment that statistically compares flakes derived from bifacial pressure flaking and soft hammer percussion flaking. Our analyses show that pressure flakes are on average lighter, shorter, narrower, and thicker than soft hammer percussion flakes. Discriminant analyses indicate that pressure flakes can be correctly classified at a rate of 70 percent in a mixed sample. Furthermore, our findings validate the assumption that pressure flakes are less variable in form compared to soft hammer percussion flakes. Based on our results, we suggest quantitatively reevaluating the presence of pressure flaking in the global archaeological record.

Outlining the knapping techniques: Assessment of the shape and regularity of prismatic blades using elliptic Fourier analysis

“…Blades produced by indirect percussion and particularly pressure debitage are generally narrower and have less side-to-side curvature than the blades produced by direct percussion. This is in line with the results of Buchanan et al (2016), who concluded that pressure flakes are narrower than soft hammer direct percussion flakes. Furthermore, although the majority of blades have similar proximal and distal width, some blades produced by direct percussion have maximal width located in the distal part of the blades, while some pressure blades have wider proximal parts.…”

“…Indirect percussion blades have higher symmetry and standardization than direct percussion blades, as predicted. In the case of flakes, using several linear measurements Buchanan et al (2016) also determined that those produced by pressure are more standardized than soft stone percussion flakes. Interestingly, they reached a different conclusion in the case of symmetry, concluding that the two groups have comparable levels of symmetry.…”

“…To evaluate the accuracy of the method in discriminating between the blades produced by different techniques, and compare it with the accuracy of the previously proposed approaches (Buchanan et al 2016;Damlien 2015), we conducted a Linear Discriminant Analysis (LDA).…”

A Synthesis of the Dibble et al. Controlled Experiments into the Mechanics of Lithic Production

“…This type of lithic experimentation allows researchers to look beyond the form of the artifacts and explore the dynamic ways past people made and used different forms of stone tools under settings that highly resemble the past knapping conditions (Johnson et al, 1978). Replicative lithic experiments allow archaeologists to explore a wide range of topics in lithic studies under a highly realistic knapping framework, including manufacturing techniques (Boëda, 1982;Bordes, 1969;Callahan, 1979Callahan, , 1985Clark, 1982Clark, , 2012Crabtree, 1966Crabtree, , 1968Crabtree, , 1970Hayden & Hutchings, 1989;Pelegrin, 2012), function (Iovita et al, 2014;Schoville et al, 2016;Shea et al, 2001;Shea et al, 2002;Sisk & Shea, 2009;Tringham et al, 1974;Villa et al, 2009), morphological characteristics (Boldurian & Hoffman, 2009;Bradbury & Carr, 1995;Bradley & Sampson, 1986;Buchanan et al, 2016;Dibble et al, 2005;Eren & Bradley, 2009;Karavanić & Šokec, 2003), curation, and use life (Andrefsky, 2006;Clarkson & Hiscock, 2011;Eren et al, 2008;Shott, 2020;Shott & Sillitoe, 2005;Shott et al, 2000) of stone tools, as well as the cognitive and technological capabilities of the prehistoric knappers (Bril et al, 2010;Eren et al, 2011a, b;Harlacker, 2003;N...…”

“…Replicative knapping experiments have shown that hard versus soft hammers can affect various flake attributes, including flake mass, linear flake dimensions, platform attributes, flake initiation, and flake termination (Bradbury & Carr, 1995;Buchanan et al, 2016;Damlien, 2015;Driscoll & García-Rojas, 2014;Schindler & Koch, 2012). These differences in flaking outcomes are often attributed to differences in force propagation mechanisms.…”