However, chimpanzee choices in our data are also closer to the equilibrium prediction and are more responsive to past history and to payoff changes, than human choices. Dozens of studies with human subjects show substantial deviations from that idealized equilibrium state. Equilibrium predictions assume mathematically that all organisms making choices correctly anticipate what others do. We show that frequencies of chimpanzee choices are close to equilibrium game theory predictions and shift as payoffs change, just as equilibrium (accurate-guessing) theory predicts. In this study, game theory is used to make predictions about choices and temporal dynamics in three abstract competitive situations with chimpanzee and human participants. However, the ability of different species to think about payoff-relevant actions of conspecifics and respond to action histories is not well understood. Interaction among organisms, in which each organism's action influences the fitness reward of the other, is ubiquitous in biological life.

The results are consistent with a tentative interpretation of game theory as explaining evolved behavior, with the additional hypothesis that chimpanzees may retain or practice a specialized capacity to adjust strategy choice during competition to perform at least as well as, or better than, humans have. The chimpanzee choices are also closer to the equilibrium prediction and more responsive to past history and payoff changes, than two samples of human choices from experiments in which humans were also initially uninformed about opponent payoffs and could not communicate verbally. Frequencies of chimpanzee choices are extremely close to equilibrium (accurate-guessing) predictions and shift as payoffs change, just as equilibrium theory predicts. We use game theory to make predictions about choices and temporal dynamics in three abstract competitive situations with chimpanzee participants. The capacity for strategic thinking about the payoff-relevant actions of conspecifics is not well understood across species.

Chimpanzee price