Geographic Constraints on Social Network Groups

Jukka-Pekka Onnela,Nicholas A Christakis,Samuel Arbesman,Marta C González,Albert-László Barabási,Matjaz Perc

doi:10.1371/journal.pone.0016939

Abstract

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.

Highlights

Social groups are common among animals and humans [1,2,3,4,5]
Dyadic Interactions and Geography We create a network of social interactions by measuring ties between individuals based on mobile phone call and text messaging data from an unnamed European country
Our result that tie strength does not vary with distance is complementary to the finding of Lambiotte et al, who report that the average duration of phone calls increases with distance, reaching a plateau around 40 km

Summary

Introduction

Social groups are common among animals and humans [1,2,3,4,5] In humans, they reflect friendship, kinship, and work relationships, and can be seen as social networks. From an evolutionary and historical perspective, the formation of such network groups – consisting of agglomerations of dyadic interactions – has been constrained by geography. Larger social units, enabled by modern technology and political organization, offer drastically different opportunities for social interactions and for group assembly over larger geographic ranges. Is the structure of ‘‘old-fashioned’’ groups similar to the large-scale groups possible in modern society? And second, what role does geography play in group formation?

Methods

Results

Conclusion