Nash Equilibrium
AdvancedA Nash equilibrium is a situation in a strategic interaction where no participant can improve their outcome by changing their own strategy, as long as the others keep theirs unchanged.
The concept is named after mathematician John Nash, who described it in 1950 and later shared the Nobel Prize in Economics in 1994 for his work on game theory.
In a Nash equilibrium, each player's strategy is the best response to the strategies of the others. No one has a reason to change on their own, so the situation is stable.
For example, in the prisoner's dilemma, both suspects confessing is a Nash equilibrium. If one suspect confesses, the other is better off confessing too, so neither wants to switch, even though both staying silent would leave both better off.
This shows that a Nash equilibrium is not necessarily the best outcome for the group. Some games have several Nash equilibria, and some have none in simple strategies. The concept is widely used to analyse competition between firms, pricing, auctions, bargaining, voting and international negotiations, helping predict likely outcomes when parties act in their own interest.
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