Strategic sacrifice resolves fairness-induced coordination failure through emergent leadership in simulated kinship...

Collective action research typically attributes coordination failure to follower free-riding. A distinct and underexplored barrier is identified here: organizer hesitancy arising from fairness norms that discourage visible role asymmetry. In fairness-sensitive communities, individuals may avoid assuming leadership roles even when coordination is collectively beneficial. Agent-based simulations of 1,250 kinship networks show that strategic sacrifice (sustained, disproportionate cost-bearing by individuals with low fairness sensitivity) enables the endogenous emergence of leadership (i.e., leaders arising through internal network dynamics rather than external assignment). These individuals incur cost premiums of 16.6% above network averages and accumulate dramatically higher social approval than non-leaders ([Formula: see text], [Formula: see text]), stabilizing coordination across the network. Notably, sacrifice-based leadership produces only a modest increase in coordination rates ([Formula: see text], [Formula: see text]); its primary function is to establish persistent coordination structures rather than to substantially increase coordination frequency. Robustness analyses confirm these patterns across alternative network specifications and participation thresholds. These findings identify a reciprocity-based pathway to informal authority in egalitarian systems: sacrifice resolves fairness-induced coordination failure by creating stable organizational structure, offering a mechanism functionally distinct from classical costly signaling.