Directedness of information flow in mobile phone communication networks

TL;DR

This paper investigates how information flows in mobile phone networks by analyzing causality trees, revealing the roles of super-spreaders, network correlations, and the time scales of rumor spreading.

Contribution

It introduces a novel analysis of causality trees in mobile networks, highlighting the impact of network topology and temporal correlations on information dissemination.

Findings

Super-spreaders and super-receivers identified

Information spread requires over 30 hours to reach a large fraction

Network correlations promote, while temporal correlations limit, information flow

Abstract

Without having direct access to the information that is being exchanged, traces of information flow can be obtained by looking at temporal sequences of user interactions. These sequences can be represented as causality trees whose statistics result from a complex interplay between the topology of the underlying (social) network and the time correlations among the communications. Here, we study causality trees in mobile-phone data, which can be represented as a dynamical directed network. This representation of the data reveals the existence of super-spreaders and super-receivers. We show that the tree statistics, respectively the information spreading process, are extremely sensitive to the in-out degree correlation exhibited by the users. We also learn that a given information, e.g., a rumor, would require users to retransmit it for more than 30 hours in order to cover a macroscopic fraction of the system. Our analysis indicates that topological node-node correlations of the underlying social network, while allowing the existence of information loops, they also promote information spreading. Temporal correlations, and therefore causality effects, are only visible as local phenomena and during short time scales. These results are obtained through a combination of theory and data analysis techniques.