Worldwide evidence of cultural similarity among co-religionists within and across countries using the World Values Survey
Cultural evolutionary theories suggest that world religions have contributed to the expansion of human cooperation, in part by consolidating beliefs, values, and practices within a culturally integrated super-ethnic identity. To test this hypothesis, we measured cultural distance between religious groups within and between countries, using the Cultural Fixation Index (CF_ST) applied to the World Values Survey (88 countries, N=243,118). We found cultural similarity between co-religionists within and across countries: Individuals who shared a religious denomination and level of religiosity were more culturally similar than those with different affiliations and levels of religiosity, even after excluding overtly religious values. Moreover, distances between denominations echoed shared historical descent (e.g., Christian denominations were culturally similar). Non-religious individuals across countries also shared cultural values, suggesting the cultural evolution of secularization. Together, results reveal the pervasive cultural signature of religion and support the role of world religions in sustaining superordinate identities that transcend geographical boundaries.