Yamamoto, Hitoshi and Isamu Okada
Some research studies have pointed out that the establishment of cooperation by metanorms as proposed by Axelrod holds only for a narrow parameter space. We closely examined the conditions under which cooperation would be established by metanorms and searched out the conditions for which cooperation could continue to exist in a stable manner. It was found that cooperation could be established by maintaining variety. It was also discovered that stability in cooperation could be robustly achieved in a relatively wide parameter space by always having a few defectors in society.