The Participation Paradox: Reluctant Citizens, Satisfied Jurors, and the Boundary Conditions of Procedural Justice in Japan’s Saiban-in (Lay Judge) System

Why do lay judges report near-universal post-participation satisfaction (97%) despite substantial pre-participation reluctance (42%)? Using three datasets—nationally representative surveys (JGSS), a near-census participant survey (N = 5,048), and a comparative internet survey—we identify a Participation Paradox comprising three anomalies: high institutional trust coexisting with reluctance; pre-participation reluctance essentially unrelated to satisfaction; and experienced participants showing lower institutional trust (d = −0.51) while maintaining equivalent fairness perceptions—termed informed skepticism. Process quality, not outcomes, drives satisfaction; fairness effects on legitimacy are almost fully mediated (95.4%), consistent with Tyler’s framework. Taiwan’s contrasting trust trajectory identifies institutional maturity as a key moderator. We further propose distinguishing allocatability (distribution of legal costs) from responsibility-taking (first-person decision undertaking) as a conceptual scaffold for theorizing judgment acceptance—the tendency to accept specific decisions reached through fair processes independently of generalized institutional trust.