Structure and tie strengths in mobile communication networks

doi:10.1073/pnas.0610245104

Structure and tie strengths in mobile communication networks

*Laboratory of Computational Engineering, Helsinki University of Technology, P.O. Box 9203, FI-02015 TKK, Helsinki, Finland;
^†Physics Department, Clarendon Laboratory, Oxford University, Oxford OX1 3PU, United Kingdom;
^§Department of Physics and Center for Complex Networks Research, University of Notre Dame, South Bend, IN 46556;
^¶Center for Cancer Systems Biology, Dana–Farber Cancer Institute, Harvard University, Boston, MA 02115;
^‖John F. Kennedy School of Government, Harvard University, Cambridge, MA 02138; and
**Department of Theoretical Physics, Budapest University of Technology and Economics, H1111, Budapest, Hungary

Edited by H. Eugene Stanley, Boston University, Boston, MA, and approved January 27, 2007 (received for review November 18, 2006)

Abstract

Electronic databases, from phone to e-mails logs, currently provide detailed records of human communication patterns, offering novel avenues to map and explore the structure of social and communication networks. Here we examine the communication patterns of millions of mobile phone users, allowing us to simultaneously study the local and the global structure of a society-wide communication network. We observe a coupling between interaction strengths and the network's local structure, with the counterintuitive consequence that social networks are robust to the removal of the strong ties but fall apart after a phase transition if the weak ties are removed. We show that this coupling significantly slows the diffusion process, resulting in dynamic trapping of information in communities and find that, when it comes to information diffusion, weak and strong ties are both simultaneously ineffective.

Footnotes

^‡To whom correspondence should be addressed. E-mail: jp.onnela{at}physics.ox.ac.uk
Author contributions: J.-P.O., J.S., J.K., and A.-L.B. performed research; J.-P.O., J.H., G.S., and D.L. analyzed data; and J.-P.O., J.S., D.L., K.K., J.K., and A.-L.B. wrote the paper.
Conflict of interest statement: A.L.B. served as a paid consultant for the phone company that provided the phone data.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0610245104/DC1.
Abbreviation:

MCG,

mobile call graph.