Table 4.

Expected profits from a left move at x₂ and from defection

Treatment	E(π2|Left)*	E(π1|Down)†	Efficiency‡, %
Single 1	44.6	46.7	85.5
Single 2§	40.0	NA	86.9
Single 1 exp*	40.7	44.0	86.4
Same 1	46.6	31.3	90.6
Same 2§	46.9	na	90.3
Random 1	40.7	30.8	82.6
Repeat single 1	41.5	42.0	85.1
Random 2§	41.2	NA	84.7

NA, not applicable. 

^*Expected payoff to player 2 from moving left at x₂, given the relative frequencies of subsequent play by player 1s and 2s. 

^†Expected payoff to player 1 from defecting at node x₃, game 1. 

^‡Efficiency is the percentage of the cooperative [50, 50] total payoff that is realized by all pairs. 

^§Note that in game 2, the move order of the outcomes [60, 30] and [50, 50] are reversed relative to game 1.