Isotopic reconstruction of social networks: geochemistry, ethnoarchaeology, and recent prehistory

人类合作演变的一个里程碑是形成了将个人与居民群体以外的其他人联系起来的社会网络。这个项目将通过研究礼物交换中象征性物品的移动来调查社交网络的发展及其在前工业化社会中的应用。网络拓宽了商品、规范、制度、信仰和思想传播的互动领域，为发展更复杂的文化提供了基石。了解现代和古代狩猎采集者的社会和交流网络将有助于揭示人类人口如何能够适应过去的气候波动并传播到整个地球，利用网络缓冲风险并变得更具弹性。考古部分将通过跟踪网络配置的变化来增加我们关于古代游牧民族如何适应极度干旱的知识，以应对自然资源的可获得性和与邻国的竞争。它还将为理解当今通过电子手段从根本上扩大网络的预期和意外后果提供一个基线。通过记录网络的最新变化，这项研究将为发展努力提供宝贵的见解，以帮助群体获得可持续的经济活动和减轻贫困。该项目开发的化学和地理空间数据产品产生了其他更广泛的影响；环境化学的景观尺度模型可用于确定非法采购动植物产品的来源。该项目将为学生和高级研究人员提供培训和国际合作机会。该项目将应用分析化学和地理空间建模来确定鸵鸟蛋壳(OES)珠子相对于其沉积或收集位置的地理原产地或出处区域。在沙漠地区，古代和现代的狩猎采集者和牧民使用OES珠子制作有价值的个人饰品，这些饰品被赠送给相互支持的关系，以增强对环境、人口和社会压力的适应能力。这些起点和沉淀点之间的距离以及物体(例如项链)中珠子来源的多样性将被用作衡量社交网络规模的指标。可以通过测量锶元素的两个同位素的比率来确定OES的来源。~(87)锶/~(86)锶的比值沿着食物链从岩石到土壤和水再到植物，最终进入动物体内，产生一种化学信号，将有机体与其获得营养的地方联系起来。该项目有三个主要目标：1)构建两个研究区域内地貌变化的地统计学模型；2)从人类学家在20世纪50年代至70年代收集的OES珠子的87SR/86Sr分析中，确定是否可以检测到最近采集者之间有良好记录的交换网络；以及3)探索过去4000年来干旱、动植物开发和仪式活动不断增加的沙漠地区OES同位素分析的潜力。这一奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

A milestone in the evolution of human cooperation was the formation of social networks linking individuals to others outside of the residential group. This project will investigate the development of social networks and their applications in pre-industrial societies by studying the movement of symbolic objects through gift exchange. Networks broadened spheres of interaction for the transmission of goods, norms, institutions, beliefs, and ideas, providing the building blocks for development of ever more complex culture. Understanding social and exchange networks in recent and ancient hunter-gatherers will shed light on how human populations were able to adapt to climatic fluctuations in the past and spread throughout the planet, using networks to buffer risk and become more resilient. The archaeological component will augment our knowledge of how ancient pastoral nomads adapted to hyper-aridity by tracking changes in network configuration in response to availability of natural resources and competition with neighbors. It will also provide a baseline for understanding the intended and unintended consequences of radically scaling up networks by electronic means today. By documenting recent changes in networks, the research will provide valuable insights for development efforts to assist groups in acquiring sustainable economic activities and alleviating poverty. Additional broader impacts derive from the chemical and geospatial data products developed in this project; landscape-scale models of environmental chemistry can be used to determine the source of illegally procured plant and animal products. The project will provide training and international collaborative opportunities for students and senior researchers.The project will apply analytical chemistry and geospatial modeling to determine the area of geographic origin, or provenience, of ostrich eggshell (OES) beads relative to their location of deposition or collection. In desert regions, ancient and recent hunter-gatherers and pastoralists used OES beads to make valued personal ornaments that were gifted to underwrite relations of mutual support that increased resilience to environmental, demographic, and social pressures. The distance between these origin and deposition points and the diversity in origin for beads in an object (e.g. a necklace) will be used as proxies for the scale of social networks. It is possible to determine the provenience of OES by measuring the ratio of two isotopes of the element strontium (Sr). The 87Sr/86Sr ratio is transmitted up the food chain from rock to soil and water to plants and ultimately into animals, creating a chemical signature linking an organism to the place where it acquired nutrition. This project has three major objectives: 1) construct geostatistical models of 87Sr/86Sr variation across the landscape in both study areas, 2) determine if well-documented exchange networks among recent foragers are detectible from 87Sr/86Sr analysis of OES beadwork collected by anthropologists in the 1950s-1970s, and 3) explore the potential of isotope analysis of OES for uncovering networks in desert regions over the last 4000 years when there was increasing aridity, plant and animal exploitation, and ritual activity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.