Self scores and combined scores in pairwise tournaments.

In addition to the wins and the scores considered in Table 2, we consider two additional measures for a memory space’s success. A memory space’s self payoff is the payoff two players with the respective memory space obtain against each other. The combined score is the sum of the memory space’s score and its self payoff. Again, winners are marked in bold face. Across all cooperation costs, we find that memory-1 strategies yield the largest self payoff. They also achieve the largest combined score if c ≤ 0.3; otherwise, for c ≥ 0.4, reactive strategies succeed. Parameters are the same as in Table 1.