Casting Doubt: Image Concerns and the Communication of Social Impact.

We investigate strategic communication about the social impact of costly prosocial actions. A 'sender' with noisy information about impact sends a cheap-talk message to a 'receiver', upon which both agents choose whether to act. In the presence of social preferences and image concerns, the sender trades off persuasion , exaggerating impact to induce receiver action, and justification , downplaying impact to cast doubt on the effectiveness of action and excuse her own passivity. In an experiment on charitable giving we find evidence for both motives. In line with our theory and a justification motive, increasing image concerns reduces communication of positive impact. [ABSTRACT FROM AUTHOR]