Data from 692 subjects in 11 experimental treatments provide a systematic exploration of the existence and nature of reciprocal behavior in two-person games. The experimental design discriminates between motivations of reciprocity and (nonreciprocal) other-regarding preferences. The existence of...

Previous research on gender differences in behavior has led to seemingly contradictory findings about generosity. From data generated by 290 subject pairs, we find that women are more sensitive than men to the costs of generous actions when deciding whether to be generous. The factors that...