Reciprocity supports cooperation in real-world collective action networks

Abstract

Evolutionary scientists argue that cooperation is central to human ecological success. Theoretical models, and behavioral experiments have found that human cooperation is conditional and context dependent, that individuals vary in their propensity to cooperate, and that cooperation can be stabilized by reciprocity within a group. However, outside of behavioral experiments, these findings have been difficult to validate with observations of cooperation in natural settings, especially in industrial societies, cash economies and structured organizational contexts. Here, we report in situ observations of behavioral cooperation and reciprocity from organizations embedded in a cash economy. We study small consumer food cooperatives or ‘food clubs’, in which members share bulk food purchases, and are considered to be heavily dependent on cooperation. We take advantage of a high-resolution purchasing dataset of all economic interactions for 1,528 individuals across 35 clubs, including 10,261 bulk purchases over a combined total of 107 years of club purchasing data. We develop a network method to detect economic reciprocity, categorize economic behavior as directly reciprocal, indirectly reciprocal, or non-reciprocal, and statistically classify individual behavioral types (reciprocator, helper, and beneficiary). Observed patterns of reciprocity confirm the central findings of theoretical and experimental studies. Reciprocity is highly abundant in most clubs, with direct reciprocity far more common (72%) than indirect reciprocity (11%). Reciprocators are the most common (69%) and the most stable behavioral type, but clubs vary significantly. Our results provide some of the first observational evidence of economic reciprocity and cooperation generally. They imply that cooperation may be a more important force in industrial societies, organizational contexts, and cash economies than currently understood. These results solidify the findings of the behavioral study of cooperation and open the door for greater study and application of cooperation in organizational management and economic policy.