Sunday 15 October 2017

The Prisoner's dilemma


John was murdered and his house was looted. 
Jack and Jill have been arrested by a senior police officer, Mr. Gaitonde. 
They have been arrested for stealing valuables from John's house. 
The police has found concrete evidence of the theft. 
However, the police has not found any reasonable sufficient evidence of murder against either one or both. 
Jack and Jill are placed in separate rooms and cannot communicate with each other. 
After a brief interrogation, Mr. Gaitonde is suspicious that both are guilty of the murder. 
Mr. Gaitonde offers them some choices. 


1. If both of them confess, each of them will receive a reduced sentence of 5 years instead of 10 years each 
2. If Jack confesses and Jill does not, then Jack will get a light sentence of 1 year, and Jill will get 10 years 
3. If Jack does not confess and Jill does, then Jill will get a light sentence of 1 year and Jack will get 10 years 
4. If both do not confess guilty to murder, they would face a full term of 2 years each for theft. 

What would you do if you were one of them? Give an answer before you read on. 

The dilemma:

The dilemma is that their own 'pay-off' is wholly dependent on the behaviour of the other prisoner. 
To avoid the worse-case scenario (10 years), the safest option is to confess and get 5 years. 
If collusion is possible they can both agree to deny (and get 2 years). 
But there is a very strong incentive to cheat because, if one denies and the other confesses, the best outcome of all is possible - that is 1 year. 

Fearing that the other may cheat, the safest option is to confess.

About the theory:

This is prisoner's dilemma and this is one of the game theories. 

Game theory is the study of human conflict and cooperation within a competitive situation. 
The key pioneers of game theory were mathematicians John von Neumann and John Nash, as well as economist Oskar Morgenstern.

The Prisoner's dilemma explains that two rational individuals might not cooperate, even if it appears that it is in their best interest to do so. 

It's application is wide spread in economics, political science, psychology, logic, computer science and biology. 

#PrisonersDilemma #GameTheory 
#Economics #PoliticalScience #Logic 
#Psychology #Biology #ComputerScience 

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