Direct reciprocity between individuals that use different strategy spaces
Fig 1
Direct reciprocity among players with different memory capacities.
a-c, Models of direct reciprocity assume that two or more players repeatedly engage in a social dilemma. In each round t, players can either cooperate (C) or defect (D). To make these decisions, players keep a record of what happened in previous rounds. Based on these records, they decide whether or not to cooperate in the current round. After each round, players update their private records. These records may be constrained by how much players remember. Here we distinguish three memory spaces. d, Memory-1 players () remember both their own and their co-player’s previous action. e, Reactive players (
) only remember their co-player’s previous action. f, Unconditional players (
) keep no records at all. The example in the first row illustrates an interaction between a memory-1 player with strategy WSLS [16] against a reactive player with strategy TFT [5].