  An agent may strategically employ a vague message to mislead an audience's
belief about the state of the world, but this may cause the agent to feel guilt
or negatively impact how the audience perceives the agent. Using a novel
experimental design that allows participants to be vague while at the same time
isolating the internal cost of lying from the social identity cost of appearing
dishonest, we explore the extent to which these two types of lying costs affect
communication. We find that participants exploit vagueness to be consistent
with the truth, while at the same time leveraging the imprecision to their own
benefit. More participants use vague messages in treatments where concern with
social identity is relevant. In addition, we find that social identity concerns
substantially affect the length and patterns of vague messages used across the
treatments.
