Department of Biology, Chatham University, Pittsburgh, Pennsylvania, USA.
Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA.
Am J Phys Anthropol. 2021 Apr;174(4):714-727. doi: 10.1002/ajpa.24159. Epub 2020 Oct 27.
As is the case among many complex motor tasks that require prolonged practice before achieving expertise, aspects of the biomechanics of knapping vary according to the relative experience/skill level of the practitioner. In archaeological experiments focused on the production of Plio-Pleistocene stone tools, these skill-mediated biomechanical differences have bearings on experimental design, the interpretation of results, and lithic assemblage analysis. A robust body of work exists on variation in kinematic patterns across skill levels but less is known about potential kinetic differences. The current study was undertaken to better understand kinetic patterns observed across skill levels during "Oldowan," freehand stone tool production.
Manual pressure data were collected from 23 novice and 9 expert stone tool makers during the production of simple stone flakes using direct hard hammer percussion.
Results show that expert tool makers experienced significantly lower cumulative pressure magnitudes and pressure-time integral magnitudes compared with novices. In expert knappers, digits I and II experienced similarly high pressures (both peak pressure and pressure-time integrals) and low variability in pressure relative to digits III-V. Novices, in contrast, tended to hold hammerstones such that pressure patterns were similar across digits II-V, and they showed low variability on digit I only.
The similar and consistent emphasis of the thumb by both skill groups indicates the importance of this digit in stabilizing the hammerstone. The emphasis placed on digit II is exclusive to expert knappers, and so this digit may offer osteological signals diagnostic of habitual expert tool production.
在许多需要长时间练习才能达到专业水平的复杂运动任务中，打制石器的生物力学方面会根据从业者相对经验/技能水平的不同而有所差异。在专注于制作上新世-更新世石器的考古实验中，这些技能介导的生物力学差异会影响实验设计、结果解释和石器组合分析。关于不同技能水平下运动学模式的变化已经有大量的研究，但对于潜在的动力学差异了解较少。本研究旨在更好地了解在“奥杜威”石器生产过程中不同技能水平下观察到的动力学模式。
在使用直接硬锤敲击法制作简单石片时，从 23 名新手和 9 名熟练石器制造者收集了手动压力数据。
结果表明，与新手相比，熟练的石器制造者经历的累积压力幅度和压力-时间积分幅度明显较低。在熟练的打制者中，第一和第二指承受的压力同样高（峰值压力和压力-时间积分），与第三至第五指相比压力变化较小。相比之下，新手在握住石锤时，压力模式在第二至第五指之间相似，仅在第一指上显示出较低的压力变化。
两个技能组拇指的相似且一致的受力表明，该手指在稳定石锤方面的重要性。熟练的打制者对第二指的重视是独特的，因此，这个手指可能提供了习惯性熟练石器生产的骨骼信号。
