Offer of a reward does not always promote trust in spatial games
This research provides counterintuitive insights into the relationship between rewards and trust for researchers modeling evolutionary game theory and social dynamics.
This paper investigates the impact of an inter-role reward mechanism in spatial trust games, where a trustor can pay to reward a trustworthy trustee. The study finds that moderate rewards promote trust by breaking mistrust dominance, but excessive rewards lead to a nonreturn strategy, suppressing trust. Additionally, more costly, but not excessive, rewards enhance investment advantage and consolidate rewarder clusters, improving trust.
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.