Abstract: Alexander (1986) first proposed the concept of indirect reciprocity, then in a book named The Biology of Moral Systems (1987), applied it to the explanation of the origins of human morality and large-scale cooperative behaviors. Since then, indirect reciprocity has obtained much academic attention. In the last decades, based on the view of Evolutionary Game Theory, researchers have carried out many studies to investigate the reputation mechanisms (such as image score, standing and tag etc) resulting in the universal existence of indirect reciprocity. However, most researches of reputation mechanisms were based on an assumption that one’s actions can be fully perceived by the others, and the results analysis in the researches were conducted merely on individual level. Future studies should pay more attention to reputation transmission on group level when information is not sufficient, and probe into the psychological mechanisms (e.g. fairness, trust) underlying indirect reciprocity and improve the ecological validity of indirect reciprocity research.

Key words: direct reciprocity, indirect reciprocity, reputation, reputation transmission