Tit-for-tat strategies make contingent cooperators prosper while defectors get excluded

Evidence

Robert Axelrod (1984) proposes not a genetic but a social evolutionary model of cooperation. He supposes that people in a large society use various strategies when they face an opportunity for beneficial cooperation with another. They can do relatively well only if they can take advantage of the cooperativeness of others or if they can selectively cooperate only with others who are contingently cooperative. In particular, he proposes following a strategy of tit for tat, in which one tries initial cooperation and then continues cooperation if the other also cooperates but stops cooperating if the other does not initially cooperate and cooperates thereafter only if the other starts cooperating. Players who follow this strategy prosper, and those who defect instead of cooperating get excluded from relations with the cooperators. — Russell Hardin, Trust and Trustworthiness, 627

Categorization

• XREF: Axelrod’s tit-for-tat maps cleanly onto the reader’s Milgrom law-merchant material: cooperative equilibria require repeated interaction and punishment of defection—the same exclusion mechanism Private judges enforced at the Champagne fairs. — connects to: Generalized reciprocity outranks tit-for-tat as a social glue — Robert D. Putnam, Bowling Alone The Collapse and Revival…, 41