Fig. 2.   Number of pairs achieving X or fewer (50, 50) outcomes in 20 trials. Subjects reach (50, 50) more often in the repeated 20-period play of the extensive form game, shown in Fig. 1, than in the repeated 20-period play of the comparable normal form game. These data support the hypothesis that move information is used in the extensive form game to inform subjects' theory-of-mind reasoning about the intentions of their counterpart.