Civic Infrastructure as Identity Technology: Modelling Behavioral Returns to Visibility

Civic infrastructure does more than provide public amenities, it shapes how individuals see one another. This paper develops a behavioral model in which public infrastructure operates as a visibility technology: by increasing the observability of individual contributions to civic life, it alters the reputational returns to prosocial effort. In equilibrium, visibility endogenously sustains civic engagement through recursive expectations, individuals exert effort when they believe others are watching and reciprocating. The model yields testable predictions on monotonicity, heterogeneity, and persistence of civic effort with respect to perceived legibility. Using evidence from the Understanding Society panel, the British Election Study, and the International Values Survey, we test these predictions across settings that differ in informational and institutional transparency. The results confirm the mechanism: greater civic visibility amplifies participation and trust where reputational payoffs are salient, but effects weaken when observability saturates, or reputational shadow prices decline. The findings suggest that investments in civic infrastructure can raise collective effort not merely by lowering costs, but by re-engineering the social optics through which reputations are formed.