Game theory is an abstract and deductive model of policymaking. It does not describe how people actually make decisions but rather how they would go about making decisions in competitive situations if they were completely rational. Thus, game theory is a form of rationalism, but it is applied in competitive situations in which the outcome depends on what two or more participants do. The choices are frequently portrayed in a «matrix»-a diagram that presents the alternative choices of each player and all possible outcomes of the game. A two-by-two matrix is the simplest; there are only two players, and each player has only two alternatives to choose from. There are four possible outcomes to this simple game, each represented by a cell in a matrix. The actual outcome depends on the choices of both Player A and Player B. In game theory, payoff refers to the values that each player receives as a result of his or her choices and those of the opponent. Payoffs are frequently represented by numerical values; these numerical values are placed inside each cell of the matrix and presumably correspond to the values each player places on each outcome. Because players value different outcomes differently, there are two numerical values inside each cell–one for each player.