A life-cycle model of human social groups produces a u-shaped distribution in group size

One of the central puzzles in the study of sociocultural evolution is how and why transitions from small-scale human groups to large-scale, hierarchically more complex ones occurred. Here we develop a spatially explicit agent-based model as a first step towards understanding the ecological dynamics of small and large-scale human groups. By analogy with the interactions between single-celled and multicellular organisms, we build a theory of group lifecycles as an emergent property of single cell demographic and expansion behaviours. We find that once the transition from small-scale to large-scale groups occurs, a few large-scale groups continue expanding while small-scale groups gradually become scarcer, and large-scale groups become larger in size and fewer in number over time. Demographic and expansion behaviours of groups are largely influenced by the distribution and availability of resources. Our results conform to a pattern of human political change in which religions and nation st...

社会文化演化研究中的核心谜题之一，便是人类群体如何且为何会从小规模社群跃迁至层级结构更为复杂的大规模社群。为此，我们构建了空间显性基于智能体（agent-based）模型，作为探索小规模与大规模人类群体生态动力学的初步尝试。类比单细胞生物与多细胞生物间的相互作用，我们提出了一套群体生命周期理论，将群体生命周期视为单细胞个体人口统计学特征与扩张行为的涌现属性。研究发现，一旦完成从小规模群体到大规模群体的跃迁，少数大规模群体将持续扩张，而小规模群体则逐渐趋于稀少；随着时间推移，大规模群体的群体规模愈发庞大，其数量却愈发稀缺。群体的人口统计学特征与扩张行为，在很大程度上受资源分布与可获取性的影响。我们的研究结果契合人类政治变迁的一类模式，该模式下宗教与民族国...