Human Ecology

, Volume 39, Issue 2, pp 131–140 | Cite as

Risk-Pooling and Herd Survival: An Agent-Based Model of a Maasai Gift-Giving System

  • C. Athena Aktipis
  • Lee Cronk
  • Rolando de Aguiar


We use agent-based modeling to study osotua, a gift giving system used by the Maasai of East Africa. Osotua’s literal meaning is “umbilical cord,” but it is used metaphorically to refer to a specific type of gift-giving relationship. Osotua relationships are characterized by respect, responsibility and restraint. Osotua partners ask each other for help only if they are in need and provide help only when asked and only if they are able. We hypothesize that under the ecologically volatile conditions in which Maasai pastoralists have traditionally lived, such a system is particularly suited to risk pooling. Here we explore whether osotua increases the viability of herds by comparing herd survivorship and stability under osotua rules to a) no exchange and b) probabilistic rules for requesting and giving livestock. Results from this model suggest that this gift-giving system can dramatically increase herd longevity through a limited pooling of risk.


Risk-pooling Reciprocity Cooperation Norms Pastoralism Maasai 



An early version of this work was presented at the Institute for Advanced Study in Princeton, New Jersey. We thank workshop participants for their helpful comments. We also thank the members of the Rutgers Behavioral Ecology Lab, who provided helpful feedback regarding the manuscript and Liz Dong for editorial assistance. This material is based upon work supported by the National Science Foundation under Grant No. SES-0345945 Decision Center for a Desert City (DCDC) and Grant F32 CA144331. Any opinions, findings and conclusions or recommendation expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).


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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • C. Athena Aktipis
    • 1
    • 2
  • Lee Cronk
    • 3
  • Rolando de Aguiar
    • 3
  1. 1.University of ArizonaTucsonUSA
  2. 2.Arizona State UniversityPhoenixUSA
  3. 3.Rutgers UniversityNew BrunswickUSA

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