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After decades of research on the topic of reciprocity, there is still no consensus about the meaning of the term. Instead, there has been a proliferation of reciprocity terms with varied definitions, some of which overlap in ways that lead to confusion for scholars studying cooperation. In this paper, we provide a summary of 34 reciprocity terms and their definitions from across a variety of disciplines. We then report the results of a survey of cooperation experts spanning biology, anthropology, economics, sociology, and psychology (N = 85) about the extent to which they consider 30 of these definitions of reciprocity to be truly reciprocity. Experts also rated the extent to which they considered seventeen hypothetical scenarios to be examples of reciprocity. We used exploratory factor analysis and found that responses clustered around four dimensions of transfers: Balanced (e.g., Balanced reciprocity), Reputation-based (e.g., Generalized reciprocity), Debt-based (e.g., Calculated reciprocity), and Unconditional (e.g., Negative reciprocity). Although researchers agreed that the term reciprocity was useful and necessary, there was low agreement among scholars about what should be considered reciprocity. However, there was high agreement that unconditional transfers, which are characterized by a lack of expectations of repayment, should not be considered reciprocity. We propose that scholars of cooperation consider using these four dimensions when referring to cooperative transfers rather than using reciprocity terms in order to facilitate communication across disciplines, resolve issues related to ambiguous definitions of reciprocity, and provide a solution to the lack of consensus about what constitutes reciprocity.

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This is an author-produced, peer-reviewed version of this article. © 2023, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International license. The final, definitive version of this document can be found online at Evolution and Human Behavior,

Available for download on Monday, July 01, 2024