title: Fundamental structures of dynamic social networks.
abstract: Social systems are in a constant state of flux, with dynamics spanning from minute-by-minute changes to patterns present on the timescale of years. Accurate models of social dynamics are important for understanding the spreading of influence or diseases, formation of friendships, and the productivity of teams. Although there has been much progress on understanding complex networks over the past decade, little is known about the regularities governing the microdynamics of social networks. Here, we explore the dynamic social network of a densely-connected population of ∼1,000 individuals and their interactions in the network of real-world person-to-person proximity measured via Bluetooth, as well as their telecommunication networks, online social media contacts, geolocation, and demographic data. These high-resolution data allow us to observe social groups directly, rendering community detection unnecessary. Starting from 5-min time slices, we uncover dynamic social structures expressed on multiple timescales. On the hourly timescale, we find that gatherings are fluid, with members coming and going, but organized via a stable core of individuals. Each core represents a social context. Cores exhibit a pattern of recurring meetings across weeks and months, each with varying degrees of regularity. Taken together, these findings provide a powerful simplification of the social network, where cores represent fundamental structures expressed with strong temporal and spatial regularity. Using this framework, we explore the complex interplay between social and geospatial behavior, documenting how the formation of cores is preceded by coordination behavior in the communication networks and demonstrating that social behavior can be predicted with high precision.
authors.affiliation: Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Vedran
authors.initials: V
authors.lastname: Sekara
authors.affiliation: Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark, Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139;
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Stopczynski
authors.affiliation: Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark, The Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark sljo@dtu.dk.
authors.forename: Sune
authors.initials: S
authors.lastname: Lehmann
mesh_terms: D003142:Communication; D006801:Humans; D007398:Interpersonal Relations; D012919:Social Behavior; D060756:Social Networking; D012944:Social Support
keywords: complex networks; computational social science; human dynamics; human mobility; social systems