Final Accepted Manuscript
MetadataShow full item record
PublisherELSEVIER SCIENCE INC
CitationDanvers, A. F., Hackman, J. V., & Hruschka, D. J. (2019). The amplifying role of need in giving decisions. Evolution and Human Behavior, 40(2), 188-193.
JournalEVOLUTION AND HUMAN BEHAVIOR
RightsPublished by Elsevier Inc.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractHamilton's rule predicts that altruism should depend on costs incurred and benefits provided, but these depend on the relative needs of the donor and recipient. Rewriting Hamilton's rule to account for relative need suggests an amplifying effect of need on relatedness, but not necessarily other relationship qualities. In a reanalysis of three studies of social discounting and a new replication, we find that relative need amplifies the effects of relatedness on giving in two samples of U.S. adults recruited online, but not U.S. undergraduates or Indian adults recruited online. Among U.S. online participants, the effect of genetic kinship was greater when the partner was perceived to be in higher need than when in lower need. In the other samples, relatedness and greater partner need were associated with greater giving, but the effect of relatedness on giving was not significantly amplified by need. Need never amplified the effect of social closeness on giving, although it did diminish the effect of closeness in U.S. undergraduates, likely reflecting a ceiling effect. These results confirm predictions from a modification of Hamilton's rule in a sample of U.S. adults, but raise important questions about why they hold in some samples but not others. They also illustrate the importance of understanding how contextual factors, such as relative need, can moderate the importance of common variables used in evolutionary cost-benefit analyses.
Note12 month embargo; published online: 8 November 2018
VersionFinal accepted manuscript
SponsorsNational Science Foundation - Program in Cultural Anthropology, Social Psychology Program [BCS-1150813]; National Science Foundation - Program in Decision, Risk, and Management Sciences [BCS-1150813]; John Templeton Foundation