Godoy-Lorite Antonia, Guimerà Roger, Sales-Pardo Marta
Departament d'Enginyeria Química, Universitat Rovira i Virgili, 43006 Tarragona, Catalonia, Spain.
Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Catalonia, Spain.
PLoS One. 2016 Jan 6;11(1):e0146113. doi: 10.1371/journal.pone.0146113. eCollection 2016.
In social networks, individuals constantly drop ties and replace them by new ones in a highly unpredictable fashion. This highly dynamical nature of social ties has important implications for processes such as the spread of information or of epidemics. Several studies have demonstrated the influence of a number of factors on the intricate microscopic process of tie replacement, but the macroscopic long-term effects of such changes remain largely unexplored. Here we investigate whether, despite the inherent randomness at the microscopic level, there are macroscopic statistical regularities in the long-term evolution of social networks. In particular, we analyze the email network of a large organization with over 1,000 individuals throughout four consecutive years. We find that, although the evolution of individual ties is highly unpredictable, the macro-evolution of social communication networks follows well-defined statistical patterns, characterized by exponentially decaying log-variations of the weight of social ties and of individuals' social strength. At the same time, we find that individuals have social signatures and communication strategies that are remarkably stable over the scale of several years.
在社交网络中，个体不断地切断联系，并以高度不可预测的方式用新的联系取而代之。社交关系的这种高度动态性对信息传播或流行病传播等过程具有重要影响。多项研究已经证明了许多因素对联系替换这一复杂微观过程的影响，但此类变化的宏观长期影响在很大程度上仍未得到探索。在此，我们研究尽管微观层面存在内在随机性，但社交网络的长期演化中是否存在宏观统计规律。具体而言，我们分析了一个拥有1000多名个体的大型组织连续四年的电子邮件网络。我们发现，尽管个体联系的演化高度不可预测，但社交通信网络的宏观演化遵循明确的统计模式，其特征是社交关系权重和个体社交强度的对数变化呈指数衰减。同时，我们发现个体具有在数年时间尺度上显著稳定的社交特征和通信策略。
