Costly Signaling and Coalition Formation Across Biological Scales

Coalition formation requires commitment verification — and costly signaling provides a general solution from bacteria to belief systems. Signals must cost more to fake than defection pays.

As coordination stakes increase, signals become increasingly "individually dominated" (appearing irrational from the individual's perspective). A structural cluster emerges: ritual, sacred markers, deviation punishment, identity fusion, evidence resistance. These are functional homologies — convergent solutions to the commitment verification problem.

The key insight: defectors pay more because they discount future coalition benefits more heavily. Evidence against beliefs can strengthen commitment by raising signal cost. Internal deviation is punished more severely than external opposition.