What Are Mixed Strategies Game Theory?


Jane Flores

Mixed Strategies Game Theory: Understanding the Concept

Game theory is a branch of mathematics that deals with studying decision-making. It involves analyzing the choices made by different agents in a given situation and their consequences.

One of the central concepts in game theory is mixed strategies, which involves players selecting their moves randomly. In this article, we will delve deeper into mixed strategies game theory and understand how it works.

The Basics of Game Theory

Before we dive into mixed strategies, let’s first understand some basic game theory concepts. Game theory involves analyzing strategic interactions between two or more individuals or groups. These interactions are often competitive, and each player’s decision affects the other player’s outcome.

In game theory, we use a matrix to represent a game. The matrix contains each player’s possible moves and the payoffs associated with each combination of moves. A payoff is the amount that a player receives as a result of their move.

Pure Strategies

In game theory, there are two types of strategies – pure strategies and mixed strategies. A pure strategy involves making a specific move every time you play the game. For example, if you always choose to go left in a particular game, then going left is your pure strategy.

Mixed Strategies

On the other hand, mixed strategies involve choosing an action randomly with certain probabilities assigned to each move. In other words, rather than always going left or right in a particular game, you might decide to go left 70% of the time and right 30% of the time.

How Mixed Strategies Work

Mixed strategies can be used in various games such as rock-paper-scissors or poker. Let us take an example of rock-paper-scissors:

  • Player 1 has three choices: rock (R), paper (P), or scissors (S).
  • Player 2 also has three choices: rock (R), paper (P), or scissors (S).

If both players choose the same move, then it’s a tie. If they choose different moves, then the winner is determined by the following rules:

  • Rock beats scissors
  • Scissors beat paper
  • Paper beats rock

Now, suppose Player 1 uses a mixed strategy of choosing rock 30% of the time, paper 30% of the time, and scissors 40% of the time. At the same time, suppose Player 2 uses a mixed strategy of choosing rock 20% of the time, paper 50% of the time, and scissors 30% of the time.

If we calculate the expected payoffs for each combination of moves, we can determine which move is most likely to result in a win. The expected payoff matrix for this example would look something like this:

R 0,0 -1,1 1,-1
P 1,-1 0,0 -1,1
S -1,1 1,-1 0,0

The numbers in each cell represent Player 1’s payoff first and Player 2’s second. For example, if both players choose rock (R), then they will tie with a payoff of 0,0.

The Importance of Mixed Strategies

Mixed strategies are essential in game theory because they allow players to make unpredictable moves, making it harder for their opponents to anticipate their next move. In some games, using a mixed strategy can even increase your chances of winning.


In conclusion, mixed strategies are a crucial concept in game theory. They involve selecting moves randomly with specific probabilities assigned to each move. By using mixed strategies, players can introduce an element of unpredictability into their gameplay and gain an advantage over their opponents.