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？是一个占主导地位的个人领导团队，还是多个人可以参与决策？ 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较小的群体并重新形成较大的群体（裂变-融合）。研究人员假设，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（个体之间的权力平等）。群体如何决定何时何地在他们的栖息地移动，谁施加最大的影响力是至关重要的，以确定群体生活的成本和效益，这项研究将提供洞察人类社会中平等主义的社会动态的出现。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水平的科学兴趣，并为本科生提供实地研究机会。此外，该项目还将促进国际合作、实践研讨会和公共科学研讨会。研究群体决策是如何做出的一个关键挑战是确定推动个人决策的动机，从而确定个人需求与集体行动之间的联系。一些证据表明，裂变融合的社会组织可能会促进平等主义的社会规范，当个人做什么或去哪里的决定与他们的个人需求不一致时，允许个人从专制的群体成员中分裂出来。本研究以野生黑手蛛猴为模型系统，结合成熟的行为观察方法、觅食理论模型和量化能量平衡的实验室技术，对裂变融合社会中的集体决策过程提供了更深入的机械理解。研究者将收集关于领导力和决策的观察数据以及关于个体精力状态的分析数据，如无创采集的尿液样本的C肽分析所示。该项目将解决三个主要假设：1）蜘蛛猴参与共同决策，2）当个体之间的冲突很高时，群体倾向于分裂，3）个体根据其生理需要而不是统治或社会权力领导。

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.