The Prisoner’s Dilemma-A classic story and thinking in game theory and game theory
The classic prisoner’s dilemma story
after a bank robbery
The police arrested two suspects, A and B, but charged them with insufficient evidence.
So the police came up with a way. The police detained the suspects separately so that the two parties could not exchange information with each other.
The police met with the two separately and offered both the following identical options:
During interrogation the next morning
If one person pleads guilty and testifies to prosecute the other party (called “betrayal” of the other party), while the other party remains silent, the person will be released immediately, and the silent person will be sentenced to 10 years in prison.
If both of them remain silent (saying that they “cooperate” with each other), they will also be sentenced to half a year in prison.
If both report on each other (“betray” each other), they will also be sentenced to 5 years in prison.
And during the period of separate confinement until the verdict is obtained, both parties A and B cannot meet (cannot exchange information or discuss)
We can think in two directions
individual benefit maximization vs group benefit maximization
1. In terms of maximizing personal interests
A is bound to choose the option that he will betray and the other party will be silent, so that A’s interests will be maximized (released)
However, A must ensure that B must be silent in order to achieve this condition
At this time, there are two questions in A’s head
1. Is B loyal enough to be silent, so that A has the opportunity to maximize his own interests???
2. Will B sacrifice himself to be sentenced to 10 years in prison to achieve A’s release???
At this time, if you are A, what kind of choice will you make??? (You can give yourself 5 minutes to think about it…)
In the case of maximizing personal interests, A will choose “betrayal”
For A, B has two choices: betrayal, silence
If B, who is lucky, chooses to remain silent, he can still be released. The worst plan is that B betrays. If he betrays himself, at least the two people will be punished “fairly” (Note 1), No matter what, I don’t want to have the possibility of being sentenced to 10 years in prison (Note 2)!!!
The same thinking also happens to B, so B will also make a “betrayal” choice.
The final result of the two people was that both parties betrayed, and each party was sentenced to 5 years in prison.
Party A and Party B are actually not wrong, they are both thinking about maximizing their own interests, and they are both making choices to avoid the worst end for themselves!
However, after the two parties made a choice, they each received a five-year prison sentence. The choices of A and B interacted with each other, and finally made themselves get a result that seemed fair or not the worst…
But I have to admit that the five-year prison sentence is also a considerable price, and it seems that it is not much better…
2. Maximize group interests
Both Party A and Party B chose to remain silent. As long as they are sentenced to prison for half a year, their friendship remains the same after they come out.
Smart people will definitely say that it would be fine if both parties choose to remain silent! Each of them will be sentenced to prison for half a year, and both parties will be a good man again after half a year, and there will be no betrayal issue to hurt their friendship.
assumptions:
1. If you were in the moment of the story, what choice would you make?
2. Let’s change the story. After the rules are finished, the police will give you 2 hours to exchange messages. After discussing with each other, you will be detained separately. What choice will you make?
How do you ensure that the other party is making the choice in the discussion with you?
3. In life, what situations are similar to the prisoner’s dilemma?