Abstract
<p>Liars permeate society, deceiving and exploiting cooperators, thereby undermining trust and cooperation. As individuals can obtain information about others through social interaction, we propose an evolutionary game model that unifies direct and indirect reciprocities to investigate the conditions necessary for the evolution of cooperation when deceptive gossip spreads. The model explicitly allows individuals to condition their behavior on reputational information and strategically manipulate that information through biased or false gossip. We find two types of lying defectors that evolve more than other possible ones; the GBBG-DEFECTORs, who spread gossip contrary to reputation they obtain about others, and the GGBG-DEFECTORs, who spread good gossip about others indiscriminately regardless of their reputation. Using analytical results and agent-based simulations, we demonstrate that these defectors are defeated by strategic discriminated cooperators (S-DISCs), who prioritize direct game experiences over gossip and ignore gossip about third parties from players with bad reputation, when information spreads rapidly and interactions are repeated. When interacting with lying defectors, S-DISC earns higher payoffs than classical direct reciprocal strategy, Tit-for-Tat, at low benefit-to-cost ratios and under the low game iterations. The population size does not have a significant impact on the evolution of S-DISC even when lying defectors spread lies. Overall, this study provides a general theoretical framework clarifying the conditions under which cooperation can evolve and remain stable when defectors spread lies.</p>