Heterogeneity in trustworthiness reshapes the spatial evolution of trust

Trust is fundamental to cooperation in social and economic interactions, yet its emergence is difficult to explain when individuals occupy asymmetric roles and differ in trustworthiness. How heterogeneous trustee behaviours interact with their spatial organisation to shape population-level trust remains unclear. Here we show that diversity in the amount returned by cooperative trustees can sustain trust even at relatively low levels of trustworthiness. This mechanism is driven by a percolation phenomenon: large clusters of trustworthiness promote trust formation within clusters but impede its outward diffusion, whereas an intermixed distribution facilitates the spread of trust while hindering its local emergence. Consequently, a moderate degree of spatial clustering of trustworthiness maximizes overall trust by balancing connectivity and nucleation. These findings reveal how spatial organisation and behavioural heterogeneity jointly govern trust formation in large populations with asymmetric interactions, and provide a framework for future studies of cooperation in structured social systems. Trust between individuals depends not only on how trustworthy people are on average, but also on how they are arranged in space. Simulations of a trust game on a lattice reveal a percolation trade-off: clustering generous partners helps trust take hold locally, but only intermediate spatial correlation lets it spread widely.