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

人类合作进化的一个里程碑是社会网络的形成，将个人与居住群体之外的其他人联系起来。这个项目将通过研究符号对象通过礼物交换的运动来研究社会网络的发展及其在前工业社会中的应用。网络扩大了商品、规范、制度、信仰和思想传播的互动领域，为日益复杂的文化发展提供了基石。了解近代和古代狩猎采集者的社会和交换网络，将揭示人类如何能够适应过去的气候波动，并在整个地球上传播，利用网络来缓冲风险，变得更有弹性。考古部分将通过跟踪网络配置的变化来响应自然资源的可用性和与邻居的竞争，从而增加我们对古代游牧民族如何适应极度干旱的认识。它还将为理解今天通过电子手段大幅扩大网络的预期和意外后果提供一个基线。通过记录网络最近的变化，这项研究将为发展努力提供宝贵的见解，以协助各群体获得可持续的经济活动和减轻贫困。本项目开发的化学和地理空间数据产品将产生更广泛的影响；环境化学的景观尺度模型可以用来确定非法采购的动植物产品的来源。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模型来确定鸵鸟蛋壳（OES）珠相对于其沉积或收集地点的地理起源区域或出处。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装饰品，并将其作为礼物，以保证相互支持的关系，从而增强对环境，人口和社会压力的恢复能力。这些起源点和沉积点之间的距离以及一个物体（例如项链）中珠子起源的多样性将被用作社会网络规模的代理。通过测量锶元素（Sr）的两种同位素的比值，可以确定OES的来源。87Sr/86Sr的比例通过食物链从岩石到土壤，从水到植物，最终进入动物体内，创造出一种化学特征，将生物体与其获得营养的地方联系起来。本项目有三个主要目标：1)构建两个研究区域87Sr/86Sr变化的地质统计模型；2)从人类学家在20世纪50年代至70年代收集的OES珠花的87Sr/86Sr分析中确定近期采集者之间有充分记录的交换网络；3)探索OES同位素分析在揭示过去4000年干旱、植物和动物开发以及仪式活动增加的沙漠地区网络方面的潜力。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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.