Offer of a reward does not always promote trust in spatial games

2026-03-07

AI Summary

This study investigates whether reward mechanisms invariably promote the evolution of trust in spatial trust games. By incorporating an inter-role reward scheme—wherein trustors incur a cost to reward trustworthy trustees—within an evolutionary game-theoretic framework and conducting large-scale numerical simulations, the authors uncover a non-monotonic relationship between rewards and trust: moderate rewards effectively enhance trust levels, whereas excessive rewards trigger non-reciprocating strategies that suppress trust evolution. The key contribution lies in demonstrating that rewards of intermediate intensity and moderate cost are most conducive to disrupting distrust-dominated equilibria, fostering clusters of rewarding agents, and thereby significantly facilitating the emergence of system-wide trust.

Technology Category

• Multiagent Systems: Mechanism Design
• Game Theory and Economic Paradigms: Mechanism Design
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust

Application Category

• Economics, Online Markets and Human Computation: Trust and reliance of crowd workers and data experts on GenAI
• Web Mining and Content Analysis: Models for Web evolution
• Responsible Web: Machine-in-the-loop, human agency and autonomy

Abstract

Trust is one of the cornerstones of human society. One of the evolutionary pressure mechanisms that may have led to its emergence is the presence of incentives for trustworthy behavior. However, this type of reward has received relatively little attention in the context of spatial trust games, which are often used to build models in evolutionary game theory. To fill this gap, we introduce an inter-role reward mechanism in the spatial trust game, so that an investing trustor can choose to pay an extra cost to reward a trustworthy trustee. With extensive numerical simulations, we find that this type of reward does not always promote trust. Rather, while moderate rewards break the dominance of mistrust, thereby favoring investment, excessive rewards eventually stimulate a nonreturn strategy, ultimately suppressing the evolution of trust. Additionally, lower reward costs do not necessarily promote trust. Instead, more costly, but not excessive, rewards enhance the advantage of the original investment, consolidating the clusters of rewarders and improving trust. Our model thus provides evidence about the counterintuitive nature of the relationship between trust and rewards in a complex society.

Problem

• trust
• reward mechanism
• spatial trust game
• evolutionary game theory
• incentives

Innovation

• spatial trust game
• inter-role reward mechanism
• evolution of trust
• nonlinear effect
• evolutionary game theory