A post by The Daily G the other day on cooperation and competition reminded me of The Prisoners’ Dilemma.
If you aren’t familiar with this, it’s a game theory developed in 1950 by a couple of math guys working at RAND It gives players the option of cooperation or defection. It’s a puzzle that, 60 years later, continues to be studied by philosophers, biologists, sociologists and politics (And bloggers, of course).
Prisoners’ Dilemma models have been applied to almost every form of human and animal interaction. Well-known examples from politics include arms races, income policies, trade bargaining, pollution reduction and exploitation of natural resources.
I don’t want to get into the complexities of game theory as a whole – mainly because I don’t understand it, and probably math geeks, game theory geeks, philosophers and all sorts of other people will be rolling over in their graves and laboratories at the mess I will make in talking about this. However, I think the Prisoners’ Dilemma is interesting to think about on its own and perhaps as a model for examples of cooperative behaviour on individual levels.
The Prisoners’ Dilemma, as formalized by Albert W. Tucker goes like this:
Two suspects are arrested by the police. The police have insufficient evidence for a conviction, and, having separated the prisoners, visit each of them to offer the same deal. If one testifies for the prosecution against the other (defects) and the other remains silent (cooperates), the defector goes free and the silent accomplice receives the full 10-year sentence. If both remain silent, both prisoners are sentenced to only six months in jail for a minor charge. If each betrays the other, each receives a five-year sentence. Each prisoner must choose to betray the other or to remain silent. Each one is assured that the other would not know about the betrayal before the end of the investigation. How should the prisoners act?
What would you do?
- If you confess and your accomplice remains silent, you go free and your accomplice goes to prison for ten years.
- If your accomplice confesses and you remain silent, you go to prison for ten years and your accomplice goes free.
- If you both confess you will both serve five years.
- If you both remain silent, you both go to prison for six months.
Your first reaction is probably to say that you should both just keep your mouths shut (cooperate) and serve only six months in jail — the best possible solution for everyone.
But then you have to hope that your accomplice is thinking the same thing or you’ll end up spending 10 years in jail. Neither of you can rationally depend on the other to keep his mouth shut, so both of you have no choice but to defect/confess and go to jail for five years — even though cooperating would have been in your best interests.
You have made a decision that goes against your own best interests because it’s impossible for you to reach a rational cooperative solution.
It’s apparently almost impossible to get rational, selfish beings to cooperate for their common good.
This conclusion has astonished and dismayed social scientists because it seems to mean there is a fundamental flaw in the social fabric. People will not cooperate, even if it’s in their best interests to do so, because individual incentive trumps the collective incentive. This would sort of mean that we are hopeless as a species, wouldn’t it?
A lot has been written to refute what has been cited as the only possible solution to the Prisoners’ Dilemma. But I don’t know. Cooperation requires a great deal of knowledge of, and trust for the other person/group. And trust isn’t rational.
Anyway, I thought this would be something interesting to puzzle over and discuss during the weekend.
I wonder if we can come up with Prisoners’ Dilemma situations in our every day life that either prove or disprove the rational impossibility of cooperation?