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Experimental tests of the tolerated theft and risk-reduction theories of resource exchange


Here we report the results of an experiment that tests the reciprocal risk reduction1 and ‘tolerated theft’ or taking hypotheses2 for why the human species is unique in having extensive exchange of resources among non-kin. We designed an experiment to determine whether, in response to variance of resource acquisition, people exchange food resources via taking or, alternatively, form reciprocal relationships based on giving. In the experiment, subjects forage individually, experience variation in resource acquisition, and then consume either by actions in which resources are taken from, or moved to, others in a group environment. The key feature of the experimental design is that individuals can transfer resources to others, attempt to take resources from others and defend against take-away attempts. Many subjects begin by attempting to take resources from others, who can resist those attempts at a cost to each. Over time, subjects shift to a cooperative strategy of voluntary reciprocal giving, a response not suggested by the instructions. These results provide evidence that people are independently able to overcome initial use of taking strategies, evaluate gains from exchange, and create endogenous reciprocal trading relationships as a response to unsynchronized variance in resource availability.

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Fig. 1: Statistical model results related to how resources are taken from and moved to others in a group environment by period.
Fig. 2: Variation in amount shared among six-person high-variance experimental groups.

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  1. Kaplan, H., Hill, K. & Rowe, V. Food-sharing among Ache foragers: tests of explanatory hypotheses. Curr. Anthropol. 26, 223–246 (1985).

    Article  Google Scholar 

  2. Blurton Jones, N. G. Tolerated theft, suggestions about the ecology and evolution of sharing, hoarding, and scrounging. Social. Sci. Inf. 26, 31–54 (1987).

    Article  Google Scholar 

  3. Hill, K. R. et al. Co-residence patterns in hunter-gatherer societies show unique human social structure. Science 331, 1286–1289 (2011).

    Article  PubMed  CAS  Google Scholar 

  4. Isaac, G. The food-sharing behavior of protohuman hominids. Sci. Am. 238, 90–108 (1978).

    Article  PubMed  CAS  Google Scholar 

  5. Hill, K. & Hawkes, K. in Adaptive Responses of Native Amazonians (eds Hames, R. & Vickers, W.) 139–188 (Academic, New York, NY, 1983).

  6. Gurven, M., Hill, K., Kaplan, H. Hurtado, A. & Lyles, R. Food transfers among Hiwi foragers of Venezuela: tests of reciprocity. Hum. Ecol. 28, 171–218 (2000).

  7. Hawkes, K., O’Connell, J. F. & Blurton Jones, N. G. Hadza meat sharing. Evol. Hum. Behav. 22, 113–142 (2001).

    Article  PubMed  CAS  Google Scholar 

  8. Gurven, M. To give and to give not: the behavioral ecology of human food transfers. Behav. Brain Sci. 27, 543–559 (2004).

    Google Scholar 

  9. Gurven, M. Reciprocal altruism and food sharing decisions among Hiwi and Ache hunter-gatherers. Behav. Ecol. Sociobiol. 56, 366–380 (2004).

    Article  Google Scholar 

  10. Hames, R. in Human Behavior and Adaptation: An Anthropological Perspective (eds Chagnon, N. et al.) 397–416 (Aldine de Gruyter, New York, NY, 2000).

  11. Gurven, M., Allen-Arave, W., Hill, K. & Hurtado, A. M. Reservation food sharing among the Ache of Paraguay. Hum. Nat. 12, 273–297 (2001).

    Article  PubMed  CAS  Google Scholar 

  12. Winterhalder, B. Diet choice, risk, and food sharing in a stochastic environment. J. Anthropol. Archaeol. 5, 369–392 (1986).

    Article  Google Scholar 

  13. Kameda, T., Takezawa, M., Tindale, R. S. & Smith, C. M. Social sharing and risk reduction: exploring a computational algorithm for the psychology of windfall gains. Evol. Hum. Behav. 23, 11–33 (2002).

    Article  Google Scholar 

  14. Kaplan, H. S., Schniter, E., Smith, V. L. & Wilson, B. J. Risk and the evolution of human exchange. Proc. R. Soc. B 279, 2930–2935 (2012).

    Article  PubMed  PubMed Central  Google Scholar 

  15. Smith, J. M. The theory of games and the evolution of animal conflicts. J. Theor. Biol. 47, 209–221 (1974).

    Article  PubMed  CAS  Google Scholar 

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We acknowledge the financial support of Chapman University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank J. Kirchner for software programming and M. Luetje for recruiting the participants.

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H.S.K., E.S., V.L.S. and B.J.W. contributed equally to designing the research, carrying out the experiments, analysing the data and writing the paper.

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Correspondence to Hillard S. Kaplan.

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Kaplan, H.S., Schniter, E., Smith, V.L. et al. Experimental tests of the tolerated theft and risk-reduction theories of resource exchange. Nat Hum Behav 2, 383–388 (2018).

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