Lying and Deception in Games

This article proposes definitions of lying, deception, and damage in strategic settings. Lying depends on the existence of accepted meanings for messages but does not require a model of how the audience responds to messages. Deception does require a model of how the audience interprets messages but does not directly refer to consequences. Damage requires consideration of the consequences of messages. Lies need not be deceptive. Deception does not require lying. Lying and deception are compatible with equilibrium. I give conditions under which deception must be damaging.