Non-Cooperative Game Theory: An Introduction
Non-cooperative game theory is a branch of modern economic theory that studies how individuals making independent decisions interact with each other in order to achieve their own objectives. This theory has become increasingly popular due to its capability to describe and explain the common behavior of agents in various market environments, from finance and insurance to public policy and politics.
Non-cooperative game theory can be used to determine optimal strategies for competitive interactions between multiple agents. It is based on a few basic assumptions, the first being that each agent has his or her own set of objectives and preferences and that they are rational and will act accordingly. Second, all agents possess perfect information and will use this information to assess their best possible options. Finally, each agent takes their own actions independently and the interactions between them all take place over time.
To better understand non-cooperative game theory, we must first understand the concept of Nash equilibrium. This is a situation in which no agent has an incentive to change their strategy, as they are all playing optimally. In other words, it is a situation in which each agent’s strategy is the best response to what all the other agents are doing.
Once a Nash equilibrium is reached, no agent can improve his/her position by changing his/her strategy; consequently all have opted for their best strategies with information to hand.In many cases, a Nash equilibrium may not exist and so the agents may need to adjust their strategies in order to reach an agreement.
Within the context of non-cooperative game theory, an important concept is that of a “payoff matrix”. This is a matrix that describes the winnings and/or losses of each of the players as a result of different strategies. This information is used in order to determine how each agent should optimally adjust their strategy.
Let us use the game of Prisoner’s Dilemma as an example. In this game, two players are accused of a crime and held in separate prison cells, unbeknownst to each other. Both can be convicted of a lesser crime due to a lack of evidence, but they are given the opportunity to either confess or remain silent. If both remain silent, they both get a lesser sentence. However, if one confesses and the other remains silent, the one who confesses goes free and the one who remains silent gets the maximum sentence. The pay-off matrix for this game can be summarized in the following table:
Confess Remain Silent
Confess Go Free Maximum Sentence
Remain Silent Maximum Sentence Lesser Sentence
In this game theory scenario, both players want to minimize their loss and/or maximize their gain, but they cannot communicate with each other and are unaware of the other’s decision. Thus, the Nash equilibrium occurs if both players remain silent, as this is the only outcome where neither player can do any better by changing their strategy.
The concept of Nash equilibrium is an important aspect of non-cooperative game theory, as it gives an indication of the stability and sustainability of any agreement reached. This concept can also be applied to situations in which agents have different preferences and interests, as it shows how an equilibrium can be reached even when none of the agents wishes to change its strategy.
In recent years, non-cooperative game theory has become increasingly popular for its ability to explain the behavior of agents in diverse economic and political settings. For example, this theory has been used to model the behavior of firms in different industrial markets, as well as the behavior of governments in areas such as tax policy and regulation. In the future, the continued development of this theory and its applications will be advantageous in helping to explain and predict the behavior of agents in a variety of different settings.