Parochial trust and cooperation across 17 societies

Angelo Romano*, Daniel Balliet, Toshio Yamagishi, James H. Liu

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


International challenges such as climate change, poverty, and intergroup conflict require countries to cooperate to solve these complex problems. However, the political tide in many countries has shifted inward, with skepticism and reluctance to cooperate with other countries. Thus, cross-societal investigations are needed to test theory about trust and cooperation within and between groups. We conducted an experimental study in 17 countries designed to test several theories that explain why, who, and where people trust and cooperate more with ingroup members, compared with outgroup members. The experiment involved several interactions in the trust game, either as a trustor or trustee. We manipulated partner group membership in the trust game (ingroup, outgroup, or unknown) and if their reputation was at stake during the interaction. In addition to the standard finding that participants trust and cooperate more with ingroup than outgroup members, we obtained findings that reputational concerns play a decisive role for promoting trust and cooperation universally across societies. Furthermore, men discriminated more in favor of their ingroup than women. Individual differences in cooperative preferences, as measured by social value orientation, predicted cooperation with both ingroup and outgroup members. Finally, we did not find support for three theories about the cross-societal conditions that influence the degree of ingroup favoritism observed across societies (e.g., material security, religiosity, and pathogen stress). We discuss the implications for promoting cooperation within and between countries.

Original languageEnglish
Pages (from-to)12702-12707
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number48
Publication statusPublished - 28 Nov 2017


ACKNOWLEDGMENTS. This work was supported by Asian Office of Aerospace Research and Development Grant FA2386-15-1-0003 and Japan Society for the Promotion of Science Grant 15H05730.

FundersFunder number
Asian Office of Aerospace Research and DevelopmentFA2386-15-1-0003
Japan Society for the Promotion of Science15H05730


    • Cooperation
    • Culture
    • Parochial altruism
    • Reputation
    • Trust


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