The Prisoner's Dilemma

[packbat]

Another classic game-theory hypothetical for you all:

Yesterday, you and an accomplice pulled off the bank job of the century - a haul large enough for each of you to retire to your favorite island paradise with no extradition to your home country. The money is all untraceably socked away in secret bank accounts, but, unfortunately, the police caught up to you on your way out of town. After a high-speed chase, you both ended up in separate cells in solitary, where you have been stewing away overnight.

This morning, the state attorney visited you in your cell.

"Okay, listen up," he said. "I know you'll just deny it if we ask, but we know you two did it, even if we can't prove it. So I'm going to offer you a deal. Even if both of you say nothing, we can get a year inside for both of you on a reckless endangerment charge for that wild driving last night. I'm willing to drop that charge and let you go if you'll testify against your partner.

"But before you start thinking about altruism and all that, I'm warning you - my partner's right down the hall, offering the exact same deal to your partner. If you clam up and your partner talks, you'll get twenty-five years and your partner will be let off scot free. If you both testify, I'll give you time off for cooperation - fifteen years apiece.

"That's the deal - your choice. Think it over. I'll be back tonight."

Assume that you do not know and have no loyalty to your accomplice - all you want is a minimum sentence for yourself. (You can make up a scenario to explain it if you like - the key part is that you're strangers, only together for one job.)

[Poll #1207554]

(Edit: Anyone interested in further reading may wish to read the Wikipedia Prisoner's Dilemma article.)

(Edit 2: The crosspost to thequestionclub may be found here.)

Comments

[bluewolfe.livejournal.com]

So 4 scenarios
I testify, he doesn't, I get off scot free, he gets 25
I testify, he testifies, We both get 10 years
I stay silent, he testifies, I get 25 years
I stay silent, he stays silent, we both get a year.

So it's between 25 and a year, or 10 and nothing. I'm going with the 10 or nothing, which has me testifying. The best case of testifying(0 years) is better than the best of staying silent (1 year) and the worst case of testifying (10 years) is better than the worst case of staying silent (25 years)

Do I have that right?

[bluewolfe.livejournal.com]

was that 15 years off the 25 year sentence? or was that a 15 year sentence. Still, my logic doesn't change much.

[packbat.livejournal.com]

15-year sentence, but you're right, your argument remains the same either way.

[mya87.livejournal.com]

I had the same reasoning. But then it looks like a lot of people are factoring in a third option, that the police are lying. I'm not sure what to make of that.

[bluewolfe.livejournal.com]

Well if this is a game, it'd be bad design to have a random surprise like that in a puzzle. Surprises work in FPS's, but now in puzzles. Save points are not a game mechanic, but a convenience for the player.

[mya87.livejournal.com]

that's why i was following that logic you described-- because i thought this was a question about game theory. now i'm just befuddled.

[packbat.livejournal.com]

Right now, I don't think it's possible to keep people from considering factors like that. Besides, people's justifications for a choice are not necessarily identical to the actual causes.