Some acts of human cooperation are not easily explained by traditional models of kinship or reciprocity. Fitness interdependence may provide a unifying conceptual framework, in which cooperation arises from the mutual dependence for survival or reproduction, as occurs among mates, risk-pooling partnerships and brothers-in-arms.

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The authors thank all the participants in the Fitness Interdependence Workshop held at Arizona State University in February 2017, including G. Roberts and H. Wasielewski who provided valuable feedback on this manuscript. We also acknowledge the support of the Department of Psychology at Arizona State University and the Human Generosity Project. We also thank S. Brown for valuable comments and feedback on this manuscript. The work of A.A. and L.C. was supported by a grant from the John Templeton Foundation (grant number 46724) and the work of D.B. was supported by European Research Council Starting Grant (number 635356). Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the John Templeton Foundation.

Author information


  1. Department of Psychology, Arizona State University, Tempe, AZ, USA

    • Athena Aktipis
    • , Jessica D. Ayers
    • , Cristina Baciu
    •  & Andrés Muñoz
  2. Department of Anthropology, Rutgers University, New Brunswick, NJ, USA

    • Lee Cronk
  3. Department of Emergency Medicine, University of New Mexico, Albuquerque, NM, USA

    • Joe Alcock
  4. Department of Experimental and Applied Psychology, VU Amsterdam, Amsterdam, the Netherlands

    • Daniel Balliet
  5. Department of Anthropology, University of California, Santa Barbara, Santa Barbara, CA, USA

    • Amy M. Boddy
  6. Institute for Cognitive and Evolutionary Anthropology, University of Oxford, Oxford, UK

    • Oliver Scott Curry
  7. Oklahoma State University, Stillwater, OK, USA

    • Jaimie Arona Krems
  8. Department of Psychology, University of Arizona, Tucson, AZ, USA

    • Daniel Sullivan
  9. Department of Psychology, University of Montreal, Montreal, Quebec, Canada

    • Daniel Sznycer
  10. Department of Biology, University of Maryland, College Park, College Park, MD, USA

    • Gerald S. Wilkinson
  11. Biodesign Institute, Arizona State University, Tempe, AZ, USA

    • Pamela Winfrey


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The authors declare no competing interests.

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Correspondence to Athena Aktipis.

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