Almost-truthful interim-biased mediation enables information exchange between agents with misaligned interests

Information necessary for decision-making is often distributed among agents with misaligned interests. In such settings receiving information is desirable for the agents, while revealing it may be privately harmful. This paper constructs a class of almost-truthful interim-biased mediation protocols that incentivize information exchange in a succinct model capturing such conflicts. The protocols in this class receive signal reports from the agents and send private messages back, almost always transmitting the received signal reports without any distortions. Each rare distorted message is deliberately designed to prevent deviations from truth-telling. Specifically, each mediator’s distortion aims at implicitly encouraging a truthful agent to take the action that is interim-optimal given her private signal report only. A deviating agent, however, receives an encouragement based on an untruthful report and thus shifts her action away from the truly interim-optimal one when facing such a distortion. As a result, the deviating agent is put to a disadvantage when the mediator distorts the signals, which is enough to ensure truthful communication when the misalignment of interests between the agents is sufficiently small.