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<h1 class = "pgc-h-arrow-right" > life is full of games, and the prisoner's dilemma brings us enlightenment</h1>
Regarding the game, many people know and have heard about it. There are games everywhere in life. So what exactly is a game?
The original meaning of the game refers to playing chess, and the extended meaning is more rich and diverse: under certain external conditions, the people participating in the project abide by the same rules, choose and implement their own different behaviors or strategies, and get the corresponding results. Sometimes, the game is also used as a verb to denote a dynamic process.
Typically, a complete game consists of five elements:
First, the participants, which can be individuals or organizations that make independent decisions and bear the consequences in the process of the game;
Second, game information is the external information that is helpful to the strategy in the hands of the participants;
Third, the set of strategies;
Fourth, the game order is the order in which game participants make strategy choices;
Fifth, the game gain is the gain and loss after the game party makes a strategic choice.
In addition, if it is divided from the specific application of the game, the game can also be divided into static game and dynamic game.
The so-called static game means that in the game, two participants make choices at the same time, or the time or order of the two people making choices is different. And the actors at the back don't know what specific actions the first actors will take.
That is to say, in the debate and advancement of the same thing, both parties involved are prone to duplication of behavior.
Dynamic game means that in the game, the actions of the two participants are sequential, and the lower actor can observe which action and strategy the first actor chooses.
Games are everywhere in our lives, and there is a classic example in game theory, which is the "prisoner's dilemma".
【Prisoner's Dilemma Game Theory】
A rich man was found dead in his home, and some of his belongings were stolen. After interrogation, the police arrested Robber A and Robber B, but both denied killing the rich man, only admitting to burglary and stealing. The case was in trouble, so the police held the two in solitary confinement, and the district attorney held one-on-one conversations with the two men.
Prosecutors told A: "The evidence for theft is conclusive, so a one-year sentence is certain." But I have a deal here that if you confess to murder, I will only sentence you to three months in prison, but your accomplices will be sentenced to ten years in prison; now if you refuse to confess and your accomplices report your homicide, you will be sentenced to ten years in prison, and he will only be sentenced to three months in prison. In addition, if you both confess to murder at the same time, then you will be sentenced to 5 years in prison at the same time. ”
This is known as the "Prisoner's Dilemma."
So how to choose between Robber A and Robber B?
Obviously, they have only two choices: admit to killing or deny killing.
Bystander Qing, it seems that the best choice strategy for the two is that neither of them admits to the murder, and then they are sentenced to 1 year. However, let us not forget that the two are held separately and lack trust and understanding, so they will not know what choices the other will make.
According to the economist Adam Smith, therefore, from the perspective of the most beneficial to the individual, the choice to admit that killing is the best strategy for the individual. Because after confessing to killing, he will only be imprisoned for 3 months. Obviously, this is much better than going to 10 years in jail without admitting to killing.
However, the premise of this strategy is that the other party denies it. Therefore, the strategy of admitting to killing people is actually a strategy of harming others and benefiting themselves.
Not only that, but there are other benefits to admitting one's own homicide. For example, if the other person confesses and denies it, he will have to go to jail for 10 years. Therefore, in the case of the two sides being isolated and unable to exchange information, the best strategy is actually for the two to confess at the same time, so that the two will only be sentenced to 5 years at most, which is better than being sentenced to 10 years.
The most reasonable option for Both Robber A and Robber B is to confess the murder to the prosecutor at the same time, a tactic in which both of them choose to admit to the murder, and to be sentenced to 5 years at the same time.
The result of such a game is called "Nash equilibrium", and its formal academic name is "non-cooperative equilibrium".
This prisoner's dilemma option has broad and profound radiating implications. Because, when individuals are choosing strategies,
This means that although there is a conflict between the individual and the collective, the pursuit of self-interested behavior by the individual will eventually lead to a "Nash equilibrium" and an ending that is beneficial to all.
From the "Nash equilibrium", we can also understand a truth: cooperation is a very favorable "self-interest strategy". But cooperation must conform to a golden rule: both parties must act in the same way.
<h1 class= "pgc-h-arrow-right" > men, games, and power</h1>
After understanding the prisoner's dilemma, let's talk about the man and the game, and the core of the man game is power.
In the movie "The Godfather", there is a line that goes like this: "Women and children can be careless, but men can't." ”
The post-90s new generation is estimated to be not very familiar with the "Bible of Men" the "Godfather". But many post-70s and post-80s are its loyal fans, because it tells the story of a man's power and strength, which can be called a game classic.
Power and the game have always been regarded as the best expression of men's charm and strength.
In the movie "The Godfather", the most presented is "cooperation" and "betrayal". Game thinking is also used the most, and the film also conveys to everyone the most favorable theory, that is, a truth based on the prisoner's dilemma: never cooperate with people who have betrayed you.
In Game Theory, this is also a famous model – the repeating prisoner game.
The rule of the repeat prisoner game is that in each individual game, the two parties involved have only two choices: cooperation or betrayal. We arrange the selection combinations of both AB parties as follows:
Cooperation + cooperation
Cooperation + betrayal
Betrayal + cooperation
Betrayal + betrayal
In the game, if both A and B cooperate, they can each get 3 points; if one party chooses to cooperate and the other party betrays, the betraying party will get 5 points, and the party who chooses to cooperate can only get 0 points; if both sides choose to betray, they will get 1 point each.
In summary, the points table of both AB parties is arranged as follows:
1. A: 3 points for cooperation, 3 points for cooperation;
2. A: 0 points for cooperation, 5 points for betrayal;
3. A: Betrayal gets 5 points, B: Cooperation gets 0 points;
4. A: Betrayal gets 1 point, B: Betrayal gets 1 point;
On this basis, let's analyze why those who choose to betray will always benefit.
Using A to analyze this fact, if A has always chosen the strategy of "betrayal", then A is bound to encounter the following two situations:
(1) B cooperates, A betrays, and A scores 5 points.
(2) B betrays, A betrays, A gets 1 point.
It can be seen that in the two scoring, A, who chooses betrayal, can get 3 points each time. Assuming that A's strategy becomes "cooperative", A will encounter the following situations:
(1) B cooperation, A cooperation, A will get 3 points.
(2) B betrays, A cooperates, and A gets 0 points.
In both scoring statistics, A can only score 1.5 points each time. Compared to A's choice of betrayal strategy, his score was significantly reduced.
So if you keep comparing it like this, you will find that if people keep choosing the "betrayal" strategy, then people will not suffer losses. From this theory, people who usually choose to break the rules will indeed get more than the average person. And this kind of person is generally a person who will betray others.
Therefore, once you see clearly that there is a problem with someone's personal credibility, you must not have any cooperation with him, and you must not expect this person to be kind or turn back to the shore.
Human nature makes it impossible for him to change, and those who choose the strategy of betrayal will only always betray others and benefit themselves.
Such a person is definitely not worth your giving him a second chance!
- The End -
Author | Tang Jingda
Edit | A grain of rice
The First Psychological Writer Group | A group of young people who like to look up at the stars
参考资料：[1] Carbery, J., & Buhrmester, D. (1998). Friendship and need fulfillment during three phases of young adulthood. Journal of Social and Personal Relationships, 15(3), 393–409.
[2] Rawlins, W. K. (1992). Friendship matters: Communication, dialectics, and the life.
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