Abstract
The study tests two competing explanations of the secularization process related to rationalizing worldviews and decreasing existential insecurity. While the former explanation argues that people are unwilling to join religious groups because of increasing mechanistic understanding of the world that clashes with religious views (and is rather irreversible), the latter argues that it is the decreasing insecurity that causes secularization and that this trend can be reversed with increasing insecurity. In the present study, 811 secular participants from the USA and Poland played a modified version of the Nash demand game, which simulates dilemmas indexing cooperative insecurity. Participants were randomly assigned to either a secure or insecure environment, manipulated by the parameters of the Nash demand game, and we assessed whether they would be willing to join costly normative groups that regulate cooperation in the game. Crucially, participants were randomly assigned either to a secular condition (choosing between a secular normative group and a group with no norms)-our manipulation check-or a religious condition (choosing between a normative group with religious framing and a group without norms)-main test between the two theories. The results showed that participants in the secular condition were more likely to choose the normative group in the insecure compared to the secure environment, but this difference was inconclusive in the religious condition. However, when re-assigning participants from insecure to secure environments and vice versa, we found strong support for the existential insecurity theory. We discuss potential explanations for the discrepancy between stated and actual behavior as well as potential motivations for joining religious normative groups. This submission has been positively recommended by PCI RR (links to Stage 1 and Stage 2 recommendations).