Grim trigger
Encyclopedia
In game theory
, grim trigger (also called the grim strategy or just grim) is a trigger strategy
for a repeated game, such as an iterated prisoner's dilemma
. Initially, a player using grim trigger will cooperate, but as soon as the opponent defects (thus satisfying the trigger condition), the player using grim trigger will defect for the remainder of the iterated game. 'Since a single defect by the opponent triggers defection forever, grim trigger is the most strictly unforgiving of strategies in an iterated game'.
In iterated prisoner's dilemma strategy competitions, grim trigger performs poorly even without noise, and adding signal errors makes it even worse. Its ability to threaten permanent defection
gives it a theoretically effective way to sustain trust, but because of its unforgiving nature and the inability to communicate this threat in advance, it performs poorly.
In Robert Axelrod
's book The Evolution of Cooperation
, grim trigger is called "Friedman", for a 1971 paper by James Friedman which uses the concept.
Game theory
Game theory is a mathematical method for analyzing calculated circumstances, such as in games, where a person’s success is based upon the choices of others...
, grim trigger (also called the grim strategy or just grim) is a trigger strategy
Trigger strategy
In game theory, a trigger strategy is any of a class of strategies employed in a repeated non-cooperative game. A player using a trigger strategy initially cooperates but punishes the opponent if a certain level of defection is observed...
for a repeated game, such as an iterated prisoner's dilemma
Prisoner's dilemma
The prisoner’s dilemma is a canonical example of a game, analyzed in game theory that shows why two individuals might not cooperate, even if it appears that it is in their best interest to do so. It was originally framed by Merrill Flood and Melvin Dresher working at RAND in 1950. Albert W...
. Initially, a player using grim trigger will cooperate, but as soon as the opponent defects (thus satisfying the trigger condition), the player using grim trigger will defect for the remainder of the iterated game. 'Since a single defect by the opponent triggers defection forever, grim trigger is the most strictly unforgiving of strategies in an iterated game'.
In iterated prisoner's dilemma strategy competitions, grim trigger performs poorly even without noise, and adding signal errors makes it even worse. Its ability to threaten permanent defection
Mutual assured destruction
Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...
gives it a theoretically effective way to sustain trust, but because of its unforgiving nature and the inability to communicate this threat in advance, it performs poorly.
In Robert Axelrod
Robert Axelrod
Robert M. Axelrod is an American political scientist. He is Professor of Political Science and Public Policy at the University of Michigan where he has been since 1974. He is best known for his interdisciplinary work on the evolution of cooperation, which has been cited in numerous articles...
's book The Evolution of Cooperation
The Evolution of Cooperation
The evolution of cooperation can refer to:* the study of how cooperation can emerge and persist as elucidated by application of game theory,* a 1981 paper by political scientist Robert Axelrod and evolutionary biologist W. D...
, grim trigger is called "Friedman", for a 1971 paper by James Friedman which uses the concept.