Reciprocal Exchange Patterned By Market Forces Helps Explain Cooperation in a Small-Scale Society
Social organisms sometimes depend on help from reciprocating partners to solve adaptive problems , and individual cooperation strategies should aim to offer high supply commodities at low cost to the donor in exchange for high-demand commodities with large return benefits [2, 3]. Although such market dynamics have been documented in some animals [4, 5, 6, 7], naturalistic studies of human cooperation are often limited by focusing on single commodities . We analyzed cooperation in five domains (meat sharing, produce sharing, field labor, childcare, and sick care) among 2,161 household dyads of Tsimane’ horticulturalists, using Bayesian multilevel models and information-theoretic model comparison. Across domains, the best-fit models included kinship and residential proximity, exchanges in kind and across domains, measures of supply and demand and their interactions with exchange, and household-specific exchange slopes. In these best models, giving, receiving, and reciprocating were to some extent shaped by market forces, and reciprocal exchange across domains had a strong partial effect on cooperation independent of more exogenous factors like kinship and proximity. Our results support the view that reciprocal exchange can provide a reliable solution to adaptive problems [8, 9, 10, 11]. Although individual strategies patterned by market forces may generate gains from trade in any species , humans’ slow life history and skill-intensive foraging niche favor specialization and create interdependence [12, 13], thus stabilizing cooperation and fostering divisions of labor even in informal economies [14, 15].
Jaeggi, A. V., Hooper, P. L., Beheim, B. A., Kaplan, H., & Gurven, M. (2016). Reciprocal Exchange Patterned by Market Forces Helps Explain Cooperation in a Small-Scale Society. Current Biology, 26(16), 2180-2187. https://doi.org/10.1016/j.cub.2016.06.019
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