Doctoral Dissertation Research: Social organization and decision-making in fission-fusion primate societies

生活在社会群体中的动物如何决定群体应该做什么？是由一个占主导地位的个体领导团队，还是由多个个体共同参与决策？这个博士论文项目将研究野生蜘蛛猴的群体决策，它们在进食时经常分裂成更小的群体，并重新形成更大的群体（裂变融合）。研究者假设裂变融合社会群体是由多个个体的能量需求驱动的，并促进了平等主义的社会组织（个体之间的平等权力）。群体如何决定迁移的时间和地点，以及谁的影响力最大，对于确定群体生活的成本和收益至关重要，这项研究将为人类社会中平等主义社会动态的出现提供洞见。该项目将为STEM领域代表性不足的学生提供学术培训和指导，从而培养K-12阶段学生对科学的兴趣，并为本科生提供实地研究机会。此外，该项目将促进国际合作、实践讲习班和公共科学研讨会。研究群体决策是如何做出的一个关键挑战是确定驱动个人决策的动机，从而确定个人需求与集体行动之间的联系。一些证据表明，当决定做什么或去哪里与个人需求不一致时，裂变融合社会组织允许个人从专制的群体成员中分离出来，从而可能促进平等主义的社会规范。本研究以野生黑手蜘蛛猴为模型系统，结合已建立的野外行为观察方法、觅食理论模型和量化能量平衡的实验室技术，为裂变聚变社会的集体决策过程提供更深入的机制理解。研究者将收集领导和决策方面的观察数据，以及通过无创尿液样本c肽分析显示的个人能量状态的分析数据。该项目将解决三个主要假设：1)蜘蛛猴参与共同决策；2)当个体之间的冲突高时，群体倾向于分裂；3)个体根据自己的生理需求而不是统治或社会权力来领导。

How do animals who live in social groups make decisions about what the group should do? Does a dominant individual lead the group, or can multiple individuals contribute to decision-making? This doctoral dissertation project will investigate group decision-making in wild spider monkeys, who frequently split into smaller groups and re-form the larger group (fission-fusion) when feeding. The investigator hypothesizes that fission-fusion social grouping is driven by the energetic needs of multiple individuals and promotes egalitarian social organization (equal power among individuals). How groups decide when and where to move in their habitat and who exerts the most influence is vital to identifying the costs and benefits of group living, and this research will provide insight into the emergence of egalitarian social dynamics in human societies. This project will support academic training and mentorship for students under-represented in STEM fields, thereby fostering interest in the sciences at the K-12 level and providing field research opportunities for undergraduate students. Additionally, this project will promote international collaborations, hands-on workshops, and public science seminars.A key challenge to studying how group decisions are made is determining the motivations driving individuals' decisions, and thus the link between individual needs and collective action. Some evidence suggests that fission-fusion social organization may promote egalitarian social norms by allowing individuals to split away from despotic group members when decisions about what to do or where to go do not align with their individual needs. Using wild black-handed spider monkeys as a model system, this study combines well-established observational field methods of behavior, foraging theory models, and laboratory techniques for quantifying energy balance, to provide a deeper mechanistic understanding of the collective decision-making process in fission-fusion societies. The investigator will collect observational data on leadership and decision-making and analytical data on individual energetic state as indicated by C-peptide analysis of non-invasively collected urine samples. The project will address three main hypotheses: 1) spider monkeys engage in shared decision-making, 2) groups tend to fission when conflicts between individuals are high, and 3) individuals lead according to their physiological need as opposed to dominance or social power.