Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts, United States of America.
PLoS One. 2011 Apr 5;6(4):e16939. doi: 10.1371/journal.pone.0016939.
Social groups are fundamental building blocks of human societies. While our social interactions have always been constrained by geography, it has been impossible, due to practical difficulties, to evaluate the nature of this restriction on social group structure. We construct a social network of individuals whose most frequent geographical locations are also known. We also classify the individuals into groups according to a community detection algorithm. We study the variation of geographical span for social groups of varying sizes, and explore the relationship between topological positions and geographic positions of their members. We find that small social groups are geographically very tight, but become much more clumped when the group size exceeds about 30 members. Also, we find no correlation between the topological positions and geographic positions of individuals within network communities. These results suggest that spreading processes face distinct structural and spatial constraints.
社交群体是人类社会的基本组成部分。虽然我们的社交互动一直受到地理因素的限制，但由于实际困难，我们无法评估这种对社交群体结构的限制的性质。我们构建了一个社交网络，其中包含个人及其最常出现的地理位置信息。我们还根据社区检测算法将个体分类为不同的群体。我们研究了不同规模的社交群体的地理跨度变化，并探索了其成员的拓扑位置和地理位置之间的关系。我们发现，小社交群体在地理上非常紧密，但当群体规模超过 30 人时，它们会变得更加聚集。此外，我们还发现网络社区内个体的拓扑位置和地理位置之间没有相关性。这些结果表明，传播过程面临着明显的结构和空间限制。
