Flexibility of theory of mind in a matrix game when partner's level is different

The development of theory of mind (ToM) was investigated as flexibility of prediction and decision-making in matrix games with 202 13-, 16-, 19-, and 24-year-old participants. The ToM flexibility of prediction and decision-making showed no significant differences among any age group. The ToM flexibility of prediction and decision-making of the 0th-order partner was better than that of the 1st-order partner. The ToM flexibility of prediction was better than the ToM flexibility of decision making. Matrix games are a feasible, effective, and discriminative way to explore higher levels of theory of mind.