Yılmaz, OnurcanUgurlar, PinarDorrough, AngelaIsler, OzanYilmaz, Onurcan2024-06-232024-06-23202301948-55061948-5514https://doi.org/10.1177/19485506231209788https://hdl.handle.net/20.500.12469/5696Dorrough, Angela/0000-0002-5645-949X; Yilmaz, Onurcan/0000-0002-6094-7162; Ugurlar, Pinar/0000-0003-2727-7803Research on cooperation between groups tends to consider a single social identity at a time. However, individuals naturally share group membership in one social category (e.g., religious belief) while diverging in membership to others (e.g., political ideology). Here, we test the effects of mixed-group membership on actual cooperative behavior relative to completely sharing (in-group) and completely diverging (out-group) group memberships. In three high-powered, preregistered, and incentivized experiments, we found evidence for our hypotheses that cooperation increases with the number of shared memberships in arbitrary (Experiment 1, N = 292) as well as naturally existing social categories such as political orientation and ethnicity (Experiment 2, N = 501) or political orientation and religious affiliation (Experiment 3, N = 292).eninfo:eu-repo/semantics/openAccesscooperationgroup membershipcross-categorizationeconomic gameArticleWOS:00110174460000110.1177/194855062312097882-s2.0-85176916748Q1Q1