Department of Economics, University of Bologna, 40126 Bologna, Italy;
Institute of Labor Economics (IZA), 53113 Bonn, Germany.
Proc Natl Acad Sci U S A. 2018 Mar 13;115(11):2728-2733. doi: 10.1073/pnas.1713496115. Epub 2018 Feb 22.
Cooperation becomes more difficult as a group becomes larger, but it is unclear where it will break down. Here, we study group size within well-functioning social-ecological systems. We consider centuries-old evidence from hundreds of communities in the Alps that harvested common property resources. Results show that the average group size remained remarkably stable over about six centuries, in contrast to a general increase in the regional population. The population more than doubled, but although single groups experienced fluctuations over time, the average group size remained stable. Ecological factors, such as managing forest instead of pasture land, played a minor role in determining group size. The evidence instead indicates that factors related to social interactions had a significant role in determining group size. We discuss possible interpretations of the findings based on constraints in individual cognition and obstacles in collective decision making.
随着群体规模的扩大，合作变得更加困难，但合作在哪个环节出现破裂尚不清楚。在这里，我们研究了在运作良好的社会-生态系统中群体规模的问题。我们考虑了阿尔卑斯山数百个社区数百年间共同采集公共资源的证据。结果表明，与该地区人口的普遍增长相比，大约六个世纪以来，平均群体规模保持了显著的稳定。人口增加了一倍多，但尽管单个群体随着时间的推移经历了波动，平均群体规模仍保持稳定。生态因素，如管理森林而不是牧场，在确定群体规模方面作用较小。相反，证据表明，与社会互动相关的因素在确定群体规模方面发挥了重要作用。我们根据个体认知的限制和集体决策的障碍，讨论了对这些发现的可能解释。
