About the Authors

Jukka-Pekka Onnela

Contributed equally to this work with: Jukka-Pekka Onnela, Samuel Arbesman

onnela@med.harvard.edu

Affiliation Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts, United States of America

Samuel Arbesman

Contributed equally to this work with: Jukka-Pekka Onnela, Samuel Arbesman

Affiliation Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts, United States of America

Marta C. González

Affiliation Department of Civil and Environmental Engineering and Engineering Systems, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America

Albert-László Barabási

Affiliations Department of Physics, Biology and Computer Science, Center for Complex Network Research, Northeastern University, Boston, Massachusetts, United States of America, Center for Cancer Systems Biology, Dana Farber Cancer Institute, Boston, Massachusetts, United States of America, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America

Nicholas A. Christakis

Affiliations Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts, United States of America, Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America, Department of Sociology, Harvard Faculty of Arts and Sciences, Cambridge, Massachusetts, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: JPO SA NAC. Analyzed the data: JPO SA. Contributed reagents/materials/analysis tools: JPO SA MCG. Wrote the paper: JPO SA ALB NAC. Processed raw phone data: MCG.