# Pri­soner’s Dilemma

TagLast edit: 22 Sep 2020 19:32 UTC by

The Prisoner’s Dilemma is a well-studied game in game theory, where supposedly rational incentive following leads to both players stabbing each other in the back and being worse off than if they had cooperated.

The original formulation, via Wikipedia:

Two members of a criminal gang are arrested and imprisoned. Each prisoner is in Solitary Confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:
If A and B each betray the other, each of them serves two years in prison
If A betrays B but B remains silent, A will be set free and B will serve three years in prison
If A remains silent but B betrays A, A will serve three years in prison and B will be set free
If A and B both remain silent, both of them will serve only one year in prison (on the lesser charge).

The “stay silent” option is generally called Cooperate, and the “betray” option is called Defect. The only Nash Equilibrium of the Prisoner’s Dilemma is both players defecting, even though each would prefer the cooperate/​cooperate outcome.

A popular variant is the Iterated Prisoner’s Dilemma, where two agents play the Prisoner’s Dilemma against each other a number of times in a row. A simple and successful strategy is called Tit for Tat—cooperate on the first round, then on subsequent rounds do whatever your opponent did on the last round.

## References

• Drescher, Gary (2006). Good and Real. Cambridge: The MIT Press. ISBN 0262042339.

# In­tro­duc­tion to Pri­son­ers’ Dilemma

30 Jun 2012 0:54 UTC
61 points

# The True Pri­soner’s Dilemma

3 Sep 2008 21:34 UTC
221 points

# The Pavlov Strategy

20 Dec 2018 16:20 UTC
268 points
(srconstantin.wordpress.com)

# The Epistemic Pri­soner’s Dilemma

18 Apr 2009 5:36 UTC
109 points

# Clas­sify­ing games like the Pri­soner’s Dilemma

4 Jul 2020 17:10 UTC
103 points
(reasonableapproximation.net)

# Ro­bust Co­op­er­a­tion in the Pri­soner’s Dilemma

7 Jun 2013 8:30 UTC
120 points

# Pri­son­ers’ Dilemma with Costs to Modeling

5 Jun 2018 4:51 UTC
123 points

# Co­op­er­at­ing with agents with differ­ent ideas of fair­ness, while re­sist­ing exploitation

16 Sep 2013 8:27 UTC
97 points

# Con­trite Strate­gies and The Need For Standards

24 Dec 2018 18:30 UTC
131 points
(srconstantin.wordpress.com)

# Real World Solu­tions to Pri­son­ers’ Dilemmas

3 Jul 2012 3:25 UTC
70 points

# Pri­soner’s Dilemma Tour­na­ment Results

6 Sep 2011 0:46 UTC
152 points

# Do­main The­ory and the Pri­soner’s Dilemma: FairBot

7 May 2021 7:33 UTC
19 points

# Co­or­di­nat­ing the Unequal Treaties

25 Nov 2021 10:47 UTC
32 points

# In­ves­ti­gat­ing Emer­gent Goal-Like Be­hav­ior in Large Lan­guage Models us­ing Ex­per­i­men­tal Economics

5 May 2023 11:15 UTC
6 points

# Black­mail, Nukes and the Pri­soner’s Dilemma

10 Mar 2010 14:58 UTC
25 points

# Pro­ject idea: an iter­ated pris­oner’s dilemma com­pe­ti­tion/​game

26 Feb 2024 23:06 UTC
8 points

# Game The­ory with­out Argmax [Part 1]

11 Nov 2023 15:59 UTC
64 points

# A Differ­ent Pri­soner’s Dilemma

14 Apr 2018 15:54 UTC
9 points

# Game The­ory with­out Argmax [Part 2]

11 Nov 2023 16:02 UTC
31 points

# A Case for Co­op­er­a­tion: Depen­dence in the Pri­soner’s Dilemma

17 Jun 2024 1:10 UTC
9 points

# 2014 iter­ated pris­oner’s dilemma tour­na­ment results

30 Sep 2014 21:23 UTC
95 points

# The Dar­win Game—Rounds 1 to 2

11 Nov 2020 1:53 UTC
48 points

# Spe­cial­ized La­bor and Coun­ter­fac­tual Compensation

14 Nov 2020 18:13 UTC
18 points
(reasonableapproximation.net)

# The Mu­tant Game—Rounds 11 to 30

23 Nov 2020 9:20 UTC
5 points

# The Mu­tant Game—Rounds 31 to 90

27 Nov 2020 21:05 UTC
18 points

# Pavlov Generalizes

20 Feb 2019 9:03 UTC
67 points

# Player of Games

29 Aug 2018 21:26 UTC
65 points

# Re-for­mal­iz­ing PD

28 Apr 2009 12:10 UTC
32 points

# [Question] A way to beat su­per­ra­tional/​EDT agents?

17 Aug 2020 14:33 UTC
5 points

# Four lev­els of un­der­stand­ing de­ci­sion theory

1 Jun 2023 20:55 UTC
12 points

# An­nounc­ing the 2014 pro­gram equil­ibrium iter­ated PD tournament

31 Jul 2014 12:24 UTC
38 points

# Most Pri­soner’s Dilem­mas are Stag Hunts; Most Stag Hunts are Schel­ling Problems

14 Sep 2020 22:13 UTC
177 points

# The Dar­win Game

9 Oct 2020 10:19 UTC
91 points

# Fair­ness vs. Goodness

22 Feb 2009 20:22 UTC
15 points

# The Dar­win Game—Rounds 21-500

21 Nov 2020 0:58 UTC
27 points

6 Feb 2021 0:12 UTC
32 points

# Defend­ing Func­tional De­ci­sion Theory

8 Feb 2022 14:58 UTC
4 points

# The Calcu­lus of Nash Equilibria

1 Apr 2022 14:40 UTC
4 points

# The Pla­ton­ist’s Dilemma: A Remix on the Pri­soner’s.

12 Apr 2022 3:49 UTC
5 points

# FDT defects in a re­al­is­tic Twin Pri­son­ers’ Dilemma

15 Sep 2022 8:55 UTC
38 points

# Con­di­tions for Su­per­ra­tional­ity-mo­ti­vated Co­op­er­a­tion in a one-shot Pri­soner’s Dilemma

19 Dec 2022 15:00 UTC
24 points

# Log­i­cal Line-Of-Sight Makes Games Se­quen­tial or Loopy

19 Jan 2024 4:05 UTC
39 points

# Refram­ing Acausal Trol­ling as Acausal Patronage

23 Jan 2024 3:04 UTC
14 points

# A free to en­ter, 240 char­ac­ter, open-source iter­ated pris­oner’s dilemma tournament

9 Nov 2023 8:24 UTC
64 points
(manifold.markets)

# Pre­dictable Defect-Co­op­er­ate?

18 Nov 2023 15:38 UTC
7 points

# Pri­soner’s Dilemma (with visi­ble source code) Tournament

7 Jun 2013 8:30 UTC
73 points

# Pri­soner’s dilemma tour­na­ment results

9 Jul 2013 20:50 UTC
54 points

# The con­tinued mi­suse of the Pri­soner’s Dilemma

23 Oct 2009 3:48 UTC
34 points

# Paper: Iter­ated Pri­soner’s Dilemma con­tains strate­gies that dom­i­nate any evolu­tion­ary opponent

2 Jun 2012 20:50 UTC
39 points

# Fixed-Length Selec­tive Iter­a­tive Pri­soner’s Dilemma Mechanics

13 Sep 2011 3:24 UTC
34 points

# Pri­soner’s Dilemma on game show Golden Balls

21 Apr 2012 0:31 UTC
28 points

# The Coun­ter­fac­tual Pri­soner’s Dilemma

21 Dec 2019 1:44 UTC
21 points

# The Truly Iter­ated Pri­soner’s Dilemma

4 Sep 2008 18:00 UTC
31 points

# Pri­soner’s Dilemma as a Game The­ory Laboratory

25 Aug 2011 14:30 UTC
22 points

# [LINK] Can­tor’s the­o­rem, the pris­oner’s dilemma, and the halt­ing problem

30 Jun 2013 20:26 UTC
22 points

# New­comb’s Prob­lem vs. One-Shot Pri­soner’s Dilemma

7 Apr 2009 5:32 UTC
14 points

# Reflex­ive Or­a­cles and su­per­ra­tional­ity: pris­oner’s dilemma

24 May 2017 8:34 UTC
14 points

# Pri­soner’s Dilemma vs the Afterlife

24 Sep 2013 16:59 UTC
19 points

# Other pre­spec­tive on re­solv­ing the Pri­soner’s dilemma

4 Jun 2013 16:13 UTC
17 points

# Another Iter­ated Pri­soner’s Dilemma Tour­na­ment?

25 May 2012 14:16 UTC
14 points

# The True Epistemic Pri­soner’s Dilemma

19 Apr 2009 8:57 UTC
24 points

# New pris­oner’s dilemma and chicken tournament

14 Sep 2011 8:00 UTC
10 points