Thresholds: A model of religious governance and evolution

Religious organizations set thresholds of belief and behavior required of their members. In a simple model of individual religious behavior, this paper shows that if a religion denies the benefits of membership to those who fall short of the threshold, it stands to gain an increase in compliance with its rules by forcing members to the edge of defection, hence the incentive to set the thresholds strategically. When members' compliance costs are private information, the model yields several regimes: a pooling contract if costs are close enough to each other, a separating contract if costs are different enough, and an expulsion solution if the proportion of high-cost types in the total membership is too low. Changes in costs and in membership composition trigger changes in thresholds and switches between regimes, thus providing a model of religious governance and evolution. We then review the history of sectarianism in the three monotheistic religions and show that the model can help account for the basic differences between them as well as explain the historical evolution of dogmas and behavioral rules within each of them. A specialized case study focuses on the evolution of Catholic religious orders.