Miniaturization optimized weapon killing power during the social stress of late pre-contact North America (AD 600-1600)

Abstract

Before Europeans arrived to Eastern North America, prehistoric, indigenous peoples experienced a number of changes that culminated in the development of sedentary, maize agricultural lifeways of varying complexity. Inherent to these lifeways were several triggers of social stress including population nucleation and increase, intergroup conflict (warfare), and increased territoriality. Here, we examine whether this period of social stress co-varied with deadlier weaponry, specifically, the design of the most commonly found prehistoric archery component in late pre-contact North America: triangular stone arrow tips (TSAT). The examination of modern metal or carbon projectiles, arrows, and arrowheads has demonstrated that smaller arrow tips penetrate deeper into a target than do larger ones. We first experimentally confirm that this relationship applies to arrow tips made from stone hafted onto shafts made from wood. We then statistically assess a large sample (n = 742) of late precontact TSAT and show that these specimens are extraordinarily small. Thus, by miniaturizing their arrow tips, prehistoric people in Eastern North America optimized their projectile weaponry for maximum penetration and killing power in warfare and hunting. Finally, we verify that these functional advantages were selected across environmental and cultural boundaries. Thus, while we cannot and should not rule out stochastic, production economizing, or non-adaptive cultural processes as an explanation for TSAT, overall our results are consistent with the hypothesis that broad, socially stressful demographic changes in late pre-contact Eastern North America resulted in the miniaturization-and augmented lethality-of stone tools across the region.

Tip cross-sectional geometry predicts the penetration depth of stone-tipped projectiles

“…One important question is why our results show a strong relationship between tip cross-sectional attributes while previous results of advocates and critics alike do not ( 3 ; 24; but see 6 ). We suggest that one reason may be that the target being penetrated may have played an important role.…”

“…Killing prey was vital for the survival of prehistoric humans, and projectile penetration depth contributes to the killing of prey [1][2][3][4][5][6][7][8][9] . A wound that is shallow is more likely to result in hunting failure relative to one that injures a critical internal organ ( 10 : 84).…”

“…While there are many potential variables that can influence stone-tipped projectile penetration depth, two often mentioned are tip cross-sectional area (TCSA) and tip cross-sectional perimeter (TCSP) (e.g. 3,[5][6][7]9,[18][19][20][21][22][23][24][25][26] ). Following Hughes 5 , these variables are defined as and TCSA = 1 2…”

“…where w tip and t tip are the width and thickness, respectively, of the point measured at the widest location on the point. Given that Sperrazza and Kokinakis 27 , Ashby 28 , Hughes 5 , and Kneubuehl 29 mathematically demonstrate target penetration is inversely proportional to tip cross-sectional area, then, all things being equal, stone-tipped projectile penetration depth should increase as TCSA and TCSP decrease (see also 6,19 ). Despite this theoretical foundation, experiments involving prehistoric replica stone tipped projectiles have not consistently supported the inverse relationship between penetration depth and TCSA or TCSP.…”

Knapping quality of local versus exotic Upper Mercer chert (Ohio, USA) during the Holocene

“…), groups once again experienced major changes in resource procurement, as the widespread trade networks and elaborate ceremonialism that had once linked much of the Midwestern United States collapsed (Lepper, 2005). However, despite the overall reduction in exchange, important changes took place during the Late Woodland that could have reinforced cultural boundaries and continued northern Ohio groups' lack of access to Upper Mercer chert, including the widespread use of the bow and arrow, increased violence, population increase, and the expansion of fortified villages with stockades and ditches (Lepper, 2005; Mika et al, 2020; Shott et al, 1993).…”