A research team led by Hitoshi Yamamoto from Rissho University clarifies what role the diversity of social norms can play in the process of evolving cooperation by means of evolutionary computation methods. The team revealed social norms that are required in the transition from non-cooperative to cooperative societies, yet are not needed in the maintenance of cooperative societies. The study was carried out by collaborating with colleagues Isamu Okada (Soka University), Satoshi Uchida (RINRI Institute), and Tatsuya Sasaki (University of Vienna). The results of the study were published in Scientific Reports.