Department of Biology, Chatham University, 1 Woodland Rd., Pittsburgh, PA, 15232, USA; Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052, USA.
Department of Biology, Chatham University, 1 Woodland Rd., Pittsburgh, PA, 15232, USA; Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052, USA.
J Hum Evol. 2018 Jun;119:14-26. doi: 10.1016/j.jhevol.2018.02.008. Epub 2018 Mar 26.
It is widely agreed that biomechanical stresses imposed by stone tool behaviors influenced the evolution of the human hand. Though archaeological evidence suggests that early hominins participated in a variety of tool behaviors, it is unlikely that all behaviors equally influenced modern human hand anatomy. It is more probable that a behavior's likelihood of exerting a selective pressure was a weighted function of the magnitude of stresses associated with that behavior, the benefits received from it, and the amount of time spent performing it. Based on this premise, we focused on the first part of that equation and evaluated magnitudes of stresses associated with stone tool behaviors thought to have been commonly practiced by early hominins, to determine which placed the greatest loads on the digits. Manual pressure data were gathered from 39 human subjects using a Novel Pliance manual pressure system while they participated in multiple Plio-Pleistocene tool behaviors: nut-cracking, marrow acquisition with a hammerstone, flake production with a hammerstone, and handaxe and flake use. Manual pressure distributions varied significantly according to behavior, though there was a tendency for regions of the hand subject to the lowest pressures (e.g., proximal phalanges) to be affected less by behavior type. Hammerstone use during marrow acquisition and flake production consistently placed the greatest loads on the digits collectively, on each digit and on each phalanx. Our results suggest that, based solely on the magnitudes of stresses, hammerstone use during marrow acquisition and flake production are the most likely of the assessed behaviors to have influenced the anatomical and functional evolution of the human hand.
人们普遍认为，石器行为所产生的生物力学压力影响了人类手部的进化。尽管考古证据表明早期人类参与了各种工具行为，但并非所有行为都同等程度地影响了现代人类手部解剖结构。更有可能的是，一种行为产生选择压力的可能性是与其相关的压力大小、从中获得的益处以及执行该行为所花费的时间的加权函数。基于这一前提，我们关注该等式的第一部分，并评估了被认为是早期人类普遍进行的石器行为相关的应力大小，以确定哪些行为对手指施加了最大的负荷。使用 Novel Pliance 手动压力系统从 39 个人类受试者中收集了手动压力数据，这些人参与了多种更新世工具行为：坚果破碎、用石锤获取骨髓、用石锤制作石片以及使用手斧和石片。手动压力分布根据行为而显著变化，尽管手的压力最低的区域（例如，近节指骨）受行为类型的影响较小。在骨髓采集和石片制作过程中使用石锤会持续对手指、每个手指和每个指骨施加最大的负荷。我们的研究结果表明，仅基于压力大小，在骨髓采集和石片制作过程中使用石锤是最有可能影响人类手部解剖和功能进化的行为。
