The paper develops a formal club‑good model of religious groups that incorporates an "own‑type bias"—a preference for interacting with individuals of the same private type (e.g., ethnicity, taste, personality). The baseline model shows how contributions to a club good suffer from a free‑rider problem that worsens with group size. Introducing a choice of club, the author defines a "perfect sorting equilibrium" in which each type joins a separate club. Proposition 2 demonstrates that such sorting only occurs when the strength of own‑type bias (α) exceeds a positive threshold \(\overline{\alpha}\); otherwise, members of the majority type have an incentive to join the minority club because the smaller club faces a milder free‑rider problem. The paper then shows that imposing a membership cost (c) – interpreted as costly sacrifice (rituals, dress codes, stigma) – can restore perfect sorting even when α is below the threshold. Proposition 3 identifies the cost level \(\overline{c}=\overline{\alpha}-\alpha\) that makes the minority club indifferent, and proves that no type‑1 member will deviate when this cost is imposed. Proposition 4 derives comparative statics for the required cost: it falls as the minority population grows, rises with the majority population, and declines as own‑type bias strengthens. The analysis predicts that high‑tension (high‑cost) religious groups are those catering to rare or exotic types. The conclusion emphasizes the dual economic (screening free‑riders) and social (sorting) roles of sacrifice, suggests extensions (type‑dependent club goods, diversity preferences), and situates the work within the broader literature on club goods, homophily, and the economics of religion.
Topics
Own‑Type Bias and the Social Function of Religious Clubs
Introduces the concept that individuals derive utility from interacting with members of their own private type, motivating a demand for homogeneous clubs beyond the traditional economic role of sacrifice.
Baseline Club Model with Private Types and Free‑Rider Dynamics
Presents the one‑club benchmark: individuals have private types, contribute to a club good, and face a free‑rider problem that worsens with larger group size; derives the unique Nash equilibrium contribution \(g_i^*=y-n\).
Perfect Sorting Equilibrium and the Threshold Own‑Type Bias (Proposition 2)
Defines perfect sorting (each type in a separate club) and shows it exists iff the own‑type bias parameter α exceeds a positive threshold \(\overline{\alpha}\) that depends on group sizes; otherwise majority members deviate to the minority club.
Costly Sacrifice as a Mechanism to Achieve Sorting (Proposition 3)
Introduces a membership cost c (interpreted as sacrifice) imposed by the minority club; demonstrates that setting \(c=\overline{\alpha}-\alpha\) restores perfect sorting even when α is below the threshold, and proves no minority member will deviate.
Determinants of Required Sacrifice Cost for Minority Groups (Proposition 4)
Derives comparative statics of the minimal cost \(\overline{c}\): it decreases with minority size, increases with majority size, and falls as own‑type bias strengthens, implying rarer types face higher sacrifice demands.
Dual Economic and Social Roles of Sacrifice in Religious Clubs
Synthesizes how sacrifice simultaneously screens free‑riders (economic role) and enables type‑based sorting (social role), highlighting the interaction between the two mechanisms and suggesting extensions.
Literature Context: Homophily, Club Goods, and the Economics of Religion
Positions the model within existing research on homophily, club‑good theory, and religious economics, citing key works (Iannaccone, Schelling, Currarini et al.) and noting the novel focus on economically neutral traits.