The Prisoner's Dilemma

[Jolly Madness]

This is a problem revolving around you and your friend, by some weird divine intervention you decided to rob a huge mansion, the first day goes by perfect, you run away with a bunch of expensive antiques and pockets full of apples. Since the mansion is still full of valuable stuff you repeat the action, but you are caught. You are seperated at the police station and are both questioned, they suspect that you two are behind the earlier robbery too, but they can't prove it.
They caught you breaking in, but this won't give you more then jail for 6 months, but if you betray your friend you can go free.
Point here is, that if you both betray each other, you'll both get 5 years in jail. If one betrays the other, while one keeps silent, the betrayer goes free and the silent one goes to jail for 10 years. If both keep silent you each get 6 months of jail.
What would you do? Betray your friend and go free or keep silent and hope for the best?

 

[stormcaller]

I think this goes in forum games?

 

[irrelevantnugget]

I think this goes in forum games?

Well, it's something you'll see if you have any kind of social sciences-course, in high school and university (I've seen it in economy, sociology, politics and psychology, yay. And I've seen it in philosophy class before that, even)

Anyhoo... If you would've asked me a few years ago, I would've picked the naïve option, and hope that the other person did as well. Now... not so. Rationally, the risks are too big, and to oversimplify it: If you say you did it, you'll be in jail anyhow. If you say you didn't do it, you have 1/2 chance not ending up in jail. If you ignore the length of the sentence, of course.

 

[stormcaller]

I think this goes in forum games?

Well, it's something you'll see if you have any kind of social sciences-course, in high school and university (I've seen it in economy, sociology, politics and psychology, yay. And I've seen it in philosophy class before that, even)

Anyhoo... If you would've asked me a few years ago, I would've picked the naïve option, and hope that the other person did as well. Now... not so. Rationally, the risks are too big, and to oversimplify it: If you say you did it, you'll be in jail anyhow. If you say you didn't do it, you have 1/2 chance not ending up in jail. If you ignore the length of the sentence, of course.

/my brain goes boom and hence
/thread

 

[OneHP]

Betray! It's the equilibrium point of the game. I have an exam which includes this problem in 8 days.

Here's the pay-off matrix, the first entry is for player 1, second for player 2.

C B
C |(0.5,0.5) (10, 0)|
B | (0, 10) (5,5) |

To find the equilibrium point(the point at which any player can be punished for moving away from their strategy) we use the min-max algorithm. We find the maximum possible time spent in jail for each strategy and then choose the one with the minimal value.

C B
C |(0.5,0.5) (10, 0)| 10
B | (0, 10) (5,5) | 5
10 5 5/5

We can see that the best strategy for both players is to Betray, risking a maximum jail time of 5 years. Co-operation risks a maximum jail time of 10 years.

(hmmmm anyway to preserve my whitespace?)

 

[Jonathan Hexley]

I swear I saw this somewhere else... In another form, but it was the same gist.

Either way, I would not mind if I got betrayed, 'cause it's only 6 months. However, I am oblivious to the world, so this may be worst than I think.

 

[s0denone]

I think this goes in forum games?

Rationally, the risks are too big, and to oversimplify it: If you say you did it, you'll be in jail anyhow. If you say you didn't do it, you have 1/2 chance not ending up in jail. If you ignore the length of the sentence, of course.

This.

 

[Dys]

Depends on the friend.
I have mates that I wouldn't betray before being subject to serious torture, and others that I wouldn't take any hits for, ever.

 

[Dommyboy]

I swear I saw this somewhere else... In another form, but it was the same gist.

Either way, I would not mind if I got betrayed, 'cause it's only 6 months. However, I am oblivious to the world, so this may be worst than I think.

Actually if you get betrayed you get 10 years in gaol. Betrayal would be the smartest option I guess because chances are that they will rat you out as well and five years is better then ten years.

 

[Jonathan Hexley]

I swear I saw this somewhere else... In another form, but it was the same gist.

Either way, I would not mind if I got betrayed, 'cause it's only 6 months. However, I am oblivious to the world, so this may be worst than I think.

Actually if you get betrayed you get 10 years in gaol. Betray would be the smartest option I guess because chances are that they will rat you out as well and five years is better then ten years.

Bit of a dick move, must admit. Well then, betray, betray betray.

 

[Scorched_Cascade]

Nash equilibrium of this is to assume that humans are manipulative and will always betray you so use a tit for tat tactic unless the PD is extended to the nth amount. Did an essay on this last week .

 

[Zac_Dai]

I'm pretty sure the best option is always to betray.

But I remember this coming up in the book The Selfish Gene by Richard Dawkins. In it I think he talks about a professor who sets the Prisoners dilemma game up to be played 100 times in a row with the participants knowing the results of each game played. Prison sentences were replaced with a point system.

In it I think it turned out that the best strategy to win the most points overall or at least draw was to play "tit for tat". Where you always start the first game by not betraying, after that you play the same option unless they betray you. If they betray you then the next game you betray them as punishment (hence tit for tat) after that you go back to not betraying until they betray you again.

Hmm hope that makes sense. Anyway Dawkins used it as a zoological argument for why altruism develops in species or something like that. I'll try to find the book again to see if I remembered it properly.

 

[MCGT]

Isn't this type of argument basically the finale of Golden Balls?

I love that bit - the look on the dumbarse's face who decided to split makes me feel so deliciously evil.

 

[Pirate Pete]

Depends on which friend. Anyone from my group through high school I'd trust to keep quiet. I think my flatmate would have at least a bit of fun if he got sent to jail, anyway. First time someone tried to rape him, he'd start to do a crap.
He also doens't plan on 'wiping' for at least a day before he has to get his prostate checked, if that's still necessary by the time we reach the necessary age for that intrusive examination.

 

[Duck Sandwich]

I swear I saw this somewhere else... In another form, but it was the same gist.

Knights O' The Ol' Republic

I would choose not to betray my friend. I would think that compared to 5 or 10 years, 6 months isn't so bad, leaving my accomplice without much incentive to betray me (assuming we both take the same choice). Unless of course, he thinks I'll betray him.

But then again.... we were both dishonest/amoral enough to break into a mansion and steal stuff, so who's to say my accomplice won't betray me because he

a) is a backstabbing bastard
b) believes that I'm a backstabbing bastard?

On second thought, I'm gonna go with that betrayal option.

If the scenario was caused by just "some weird divine intervention" as opposed to the conscious choice to break in said mansion, then ignore the last paragraph.

 

[Jonathan Hexley]

I swear I saw this somewhere else... In another form, but it was the same gist.

Knights O' The Ol' Republic

Never played it.

 

[Roadie]

We'll assume that the friend in question is my best friend, a fellow Escapist member by the alias of "Helmet."

Taking that into account, I'd hold my tongue. I know, without a doubt in my mind, that he's got my back. I'd stay silent, he'd do the same, and we'd only have six months. Not too bad.

Any of my other friends, though.....not quite sure. My friends suck.

 

[Duck Sandwich]

Never played it.

Knights O' The Ol' Republic was the first and only time I had heard it. (surprisingly, it never came up in any high school philosophy discussion)

In it, a computer asks you if you would betray one Zaalbar, one of your party members in said situation. If you say no, the computer will explain to you that you made the "wrong" choice, because "Zaalbar's family is mired in treachery." His entire life, he has been exposed to treachery, thus making him more likely to betray others.

 

[Jonathan Hexley]

Never played it.

Knights O' The Ol' Republic was the first and only time I had heard it. (surprisingly, it never came up in any high school philosophy discussion)

In it, a computer asks you if you would betray one Zaalbar, one of your party members in said situation. If you say no, the computer will explain to you that you made the "wrong" choice, because "Zaalbar's family is mired in treachery." His entire life, he has been exposed to treachery, thus making him more likely to betray others.

Thank you, now if I ever play it, I'll learn to be a heartless bastard when it comes to that.

Also, I just remembered, it's the final round of Golden Balls where I heard it.

 

[Helmet]

We'll assume that the friend in question is my best friend, a fellow Escapist member by the alias of "Helmet."

Taking that into account, I'd hold my tongue. I know, without a doubt in my mind, that he's got my back. I'd stay silent, he'd do the same, and we'd only have six months. Not too bad.

Any of my other friends, though.....not quite sure. My friends suck.

Yeah, most of our friends do suck. But I'm gonna have to agree with Mr. Roadie in this one. We stay silent and it's only six months, right? I can live with that.