How Atlatl Darts Behave: Beveled Points and the Relevance of Controlled Experiments

Abstract

Beveled retouch on stone projectile points has often been considered as a device to spin and stabilize a projectile. A recent paper showed that a beveled point will spin a small shaft under tightly controlled laboratory conditions. However, this experiment has little relevance for real projectiles such as atlatl darts, which flex dramatically and spin unevenly inflight, quite independent of point form. The spinning is related to the flexibility of the dart, which is necessary for spearthrower functión. A beveled point cannot spin a dart in the air, but is likely to cause some rotation when encountering a solid target like flesh. Beveled points are probably not related to spinning either darts or arrows inflight and present a good example of why we need to have both theoretical understanding and experimental observations of details of projectile behavior before interpreting artifacts. Spinning in a carcass could make beveled points more lethal, but the suggestion that beveling mostly results from sharpening and other modification of stone points remains the best explanation.

Why Are Clovis Fluted Points More Resilient than Non‐Fluted Lanceolate Points? A Quantitative Assessment of Breakage Patterns Between Experimental Models

“…() and Pettigrew et al . () on the role of bevelled blade edges. Using fluid‐dynamics modelling and controlled wind‐tunnel experiments, Lipo et al .…”

“…() suggested that bevelled‐edge projectile points would have spun in flight after being launched by hand or from an atlatl, and this in‐flight rotation would have increased the accuracy for ballistic shafts. However, Pettigrew et al .’s () less‐controlled experiments, conducted outdoors using darts launched from atlatls by individuals (and thus more analogous to the behaviour that ultimately produced the archaeological record), suggested that bevelled‐edged projectile points do not induce ballistic shafts to rotate in flight. In effect, the complexity and sheer number of variables present in reality—and absent in Lipo et al .’s () highly controlled experiments—seem to overwhelm point‐edge bevels as the predominant causal factor for in‐flight shaft spinning.…”

Test, Model, and Method Validation: The Role of Experimental Stone Artifact Replication in Hypothesis-driven Archaeology

“…Further, excavation is unrepeatable and if one variable/trend/pattern is observed it may be difficult to determine how "typical" this may have been in other regions or temporal spans where such evidence is not currently available. In direct contrast to this, experiments might be considered to have high "internal validity": they can be repeated, and their parameters and variables might be controlled and manipulated in multiple ways (Mesoudi 2011, 135; see also discussion in Clarkson, Haslam, and Harris 2015a, 121;Pettigrew et al 2015). There is, however, an inevitable cost to this high internal validity: no experiment can "re-run" prehistory with exact precision, and its relationship to the parameters of direct interest (i.e., the archaeological record) requires the imposition of specific assumptions and inferences to give it archaeological meaning.…”

“…It all depends on the hypothesis being tested. Many hypotheses would benefit from multiple replications that systematically modify relevant factors and juxtapose the results (Eren et al 2011a(Eren et al :2014Lycett and Eren 2013a;Mesoudi 2011; see also Carr and Bradbury 2010;Marsh and Ferguson 2010;Pettigrew et al 2015).…”

The role of experimental knapping in empirically testing key themes in the evolution of lithic technology: reduction intensity, efficiency and behavioural complexity

“…Such studies rely on relatively straightforward uniformitarian assumptions about the material and chemical properties of stones and the objects with which they interact. These studies examine traces of residue and usewear (Braun et al 2008b;Claud et al 2015;Collins 2008;Key 2013;Key et al 2015;Lemorini et al 2014;Lerner et al 2007;Macdonald 2014;Miller 2015;Newcomer et al 1986;Olausson 1983a;Smallwood 2015), the functionality of particular tools (Bar-Yosef et al 2012;Cheshier and Kelly 2006;Clarkson et al 2015a;Couch et al 1999;Eren and Andrews 2013;Friis-Hansen 1990;Galán and Domínguez-Rodrigo 2014;Hunzicker 2008;Key and Lycett 2014; in press-a; in press-c; Key et al 2016;Lipo et al 2012;Machin et al 2007;Nigra and Arnold 2013;Pétillon et al 2011;Pettigrew et al 2015;Quinn et al 2008), projectile technologies (Barton and Bergman 1982;Bergman and Newcomer 1983;Brindley and Clarkson 2015;Clarkson 2016;Crombé et al 2001;Fischer et al 1984;Huckell 1982;Hutchings 2011;Iovita et al 2014;Lombard et al 2004;Moss and Newcomer 19...…”