Social networks in modern societies are highly structured, usually involving frequent contact with a small number of unrelated ‘friends’ 1 . However, contact network structures in traditional small-scale societies, especially hunter-gatherers, are poorly characterized. We developed a portable wireless sensing technology (motes) to study within-camp proximity networks among Agta and BaYaka hunter-gatherers in fine detail. We show that hunter-gatherer social networks exhibit signs of increased efficiency 2 for potential information exchange. Increased network efficiency is achieved through investment in a few strong links among non-kin ‘friends’ connecting unrelated families. We show that interactions with non-kin appear in childhood, creating opportunities for collaboration and cultural exchange beyond family at early ages. We also show that strong friendships are more important than family ties in predicting levels of shared knowledge among individuals. We hypothesize that efficient transmission of cumulative culture 3,​4,​5,​6 may have shaped human social networks and contributed to our tendency to extend networks beyond kin and form strong non-kin ties.

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We thank J. Lewis and R.K. Schlaepfer for help in the field. We thank R.K. Schlaepfer and RKSmedia for producing the accompanying movies, and R. Foley and J. Bertranpetit for comments. We also thank our assistants in Congo and the Philippines, as well as the Agta and BaYaka communities. This project was funded by the Leverhulme Trust grant RP2011-R-045 to A.B.M., M.G.T. and R.M. R.M. also received funding from European Research Council Advanced Grant AdG 249347. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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  1. Department of Anthropology, University College London, London WC1H 0BW, UK

    • A. B. Migliano
    • , A. E. Page
    • , G. D. Salali
    • , S. Viguier
    • , M. Dyble
    • , J. Thompson
    • , Nikhill Chaudhary
    • , D. Smith
    • , J. Strods
    • , R. Mace
    •  & L. Vinicius
  2. Department of Condensed Matter Physics and Institute for Biocomputation and Physics of Complex Systems, University of Zaragoza, 50009 Zaragoza, Spain

    • J. Gómez-Gardeñes
  3. Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK

    • M. G. Thomas
  4. School of Mathematical Sciences, Queen Mary University of London, London E1 4NS, UK

    • V. Latora


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A.B.M. conceived the project, S.V. designed the motes, A.B.M., M.D., J.T., A.E.P., D.S., G.D.S., N.C. and S.V. collected data, G.D.S. provided video images from Congo and collected data on plant knowledge, J.G.-G. and V.L. performed social network analysis, J.G.-G., S.V., A.E.P., M.D., D.S., N.C., J.S., J.T., V.L., L.V and A.B.M. analysed the data, R.M. commented on the manuscript, and A.B.M., L.V., M.G.T. and V.L. wrote the paper with help from all other authors.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to A. B. Migliano.

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    Supplementary Information

    Supplementary Figures 1-5, Supplementary Tables 1-4.


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    Supplementary Video 1

    BaYaka Pygmies from Congo Brazzaville performing the ‘Bobe’ forest spirits ritual. Bobe lasts for hours during the night. Women sing polyphonic music and play drums with children. After some time, adult men believed to be possessed by forest spirits are attracted by the singing and come into the camp to dance. The ritual is believed to be important for group cohesion. The video also shows children mimicking the adult performance of the forest spirits ritual in an unsupervised play group. Video footage shot by Gul Deniz Salali between March and July 2014. Video edited by Rodolph Schlaepfer (RKSmedia).

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