This paper reports an experiment examining the effect of social norms on pro-social behavior. We test two predictions derived from work in psychology regarding the influence of norms. The first is a "focusing" influence, whereby norms only impact behavior when an individual's attention is drawn...

Reciprocity is common in economic and social domains, and it has been widely documented in the laboratory. While positive and negative reciprocity are observed in investment and ultimatum games, respectively, prior laboratory studies often neglect the effect of time delays that are common in...