Case studies of cartels and recent theory suggest that repeated communication is key for stable cooperation in environments where signals about others' actions are noisy. However, empirically the exact role of communication is not well understood. We study cooperation under different monitoring...

Being perceived as trustworthy comes with substantial economic benefits in many situations. Making other people think you are a trustworthy person may, therefore, be an important motive for charity and other forms of prosocial behavior, provided these activities work as signals of...