A situation arises where two or more characters have two choices: cooperate with each other, or betray each other. Unfortunately for them, although everyone cooperating would be better than everyone betraying, each of them would be better off betraying. Furthermore, they are unable to communicate with each other, and each must therefore make his choice in ignorance of the other person's choice, and knowing that the other person will be ignorant of his choice until all choices have been made and tallied. This usually leads them to betray en masse leaving everyone worse off, but in some instances they can overcome this and cooperate, usually by trust or commitment.
The classic example is two prisoners (hence the name) who are caught and are being charged with some minor offence that the prosecution can prove. But the prosecution wants them for some other crime for which it has no proof. So an offer is made to each prisoner: if he rats out his partner, no charges will be pressed and he will go free...unless his partner rats him out too. If that happens, both get charged with the bigger crime. If both stay quiet, they both get time for the minor charge; if one partner remains silent and the other betrays him, the one who tattled on his partner will go free while his partner is charged with both crimes. Although both cooperating is better than both betraying, it is individually better to betray no matter what your partner does. If you ever get into one of these situations, you'd better hope the other person doesn't have Chronic Backstabbing Disorder.
Note that for cops, a common tactic of Lying to the Perp involves pretending the other guy talked.
See Mexican Standoff for a more specific example of this trope. Related to Cold Equation, Teeth-Clenched Teamwork, We ARE Struggling Together and Inevitable Mutual Betrayal. Possibly related to A House Divided. Contrast Rats in a Box and Power of Trust.
- Discussed in Tom Strong. Tom, attempting to prevent his world from being taken over by super-advanced Aztecs, is captured by them and released by their cyber-god, who asks to be released from his virtual prison in return. Though Tom is wary that the god will continue to take over parallel worlds, he keeps the bargain. The god chooses to quit the Aztec conquest, ruling the worlds that have already been conquered, and explains to Tom why he chose to trust him based on this dilemma.
- In The Incredible Hercules, both Hercules and his partner Amadeus Cho are captured by the Greek god Hephaestus. The rooms they're trapped in both have a switch which will open the other cell's door and allow escape, but will flood the room of the person who pressed it with a gas that not even Hercules can survive. Once the countdown starts, both Herc and Cho press their buttons instantly, setting each other free. Hilariously, Hephaestus hadn't considered this possiblity and was highly irritated.
- In chapter 33 of Harry Potter and the Methods of Rationality, Harry and Draco find themselves in one of these in the combat games — due to how the scores stand, they need to work together to beat Hermione, and only after beating her can they turn on each other to determine the final winner. If their armies pick each other off beforehand "accidentally", that'll make the final battle that much easier... but if they do too much of that, they won't beat Hermione in the first place. Cue flashbacks to rationality training, in which Harry taught Draco about the Prisoner's Dilemma, and pointed out many ways that it could be bypassed — for example, as Draco immediately pointed out, a pair of Death Eaters would never defect, because the Dark Lord would kill them for their betrayal. But in this case, none of these ways apply — including, to Harry's disappointment, the "we're similar enough that we'll surely make the same choice" method — so they need to come up with another solution. They Take a Third Option and abuse the loopholes in how the scoring system handles turncoat soldiers.
- In The Long Earth, selection pressure from being spread among countless alternate Earths and interacting with sapient but very alien nonhumans creates a hyperintelligent Human Subspecies, and the government orders their largest concentration nuked. As the setting lacks an inter-dimensional communication system, the officer-in-charge has to decide whether or not to carry out the order. The Hero gives them a damned good reason to do no such thing:
I guess my final point is a practical one. You can't get them all, here today. Doctor, you say you can hunt the rest down. I doubt it. They're too smart. They'll find ways to evade us we haven't even thought of. You won't kill them all. But they'll remember you tried.
- In The Nexus Series, this is stated to be the nature of the human/posthuman divide. Posthumans are used to an ongoing pogrom, so they hit baselines whenever and wherever they see the opportunity.
...in Iterated Prisoners Dilemma, the winning strategy is to cooperate with strangers. But if you meet someone whos betrayed you in the past, whos defected against you, you betray them. If you treat them this way, if you treat posthumans as slaves, if you torture them, if you make them prisoners Youll drive them to want revenge. Youll make them paranoid and angry. You may drive them insane. Youll create the war that none of us can win. Prisoners dilemma is always iterated in the real world. Defection is a sound strategy when youre playing against defectors.
- Atomic Rockets has a whole lot of them gathered in one place here.
- Shows up (and is referred to by name) in the climax of Star Trek: Federation. The two Enterprises are trapped inside the multisingularity. Neither has enough power to escape on their own. Either could maneuver so as to steal spatial distortion from the other, which would enable their ship to escape while dooming the other. Alternately, they could maneuver so as to essentially bounce a distortion wave between them, which if they get the timing perfect will enable both ships to steal spatial distortion from the singularity itself, but will destroy both ships if the timing is off. But neither Enterprise has working comms, so they have no way of knowing what the other is going to do.
- In Drive, Nino and the Driver would be better off if the Driver gave the money back and promised never to talk about it, and Nino left him alone. Of course Nino can't trust him, and decides it's better to kill him.
- The Dark Knight has an explicit but a little more sadistic Prisoner's Dilemma with actual prisoners. In the boat sequence, each boat has a detonator to a bomb on the other boat. If they blow the other boat, their own bomb is disarmed. One prisoner even hints at one of the usual solutions to Prisoner's Dilemmas committing not to blow the other boat by ditching the detonator. Of course this being the Joker, he has a secondary detonator set to blow both boats if they cooperate, which Batman stops him from doing.
- In The Edukators, when Jan and Julie got caught breaking and entering by Hardenberg in his house, it would be better for all of them if Hardenberg could credibly promise not to tell anyone about it and they chose not to kidnap him.
- In Murder by Numbers the detectives try to pull a classic Prisoner's Dilemma in the interrogation scene, but the trust between the prisoners and the arrival of the lawyers prevents the defection.
- In the French film Two Days One Night, the owners of a factory offer the employees a bonus if they agree to fire the protagonist, who happens to be the least productive employee (due to her clinical depression). In the long run, it might be better for the employees to stand together and preserve their collective bargaining power. However, in the short run, many of the employees really need the bonus money, and thus vote almost unanimously to fire the protagonist.
- In Ocean's 8 Debbie Ocean ended up on the wrong side of one with her art dealer/scammer boyfriend Claude Becker. They were both arrested for the scam but while she stayed silent, he not only talked by framed her as the mastermind for what had been his scam. So he got off and she was locked up for five years.
- This was an element of gameplay in The Mole. It was better for contestants to work together and give maximum effort in challenges, because that increased the pot that they were playing for. However, since The Mole was sabotaging the game, and players who incorrectly guessed the identity of The Mole faced risk of elimination in the quiz at the end of the episode, contestants would sometimes sabotage challenges in order to draw false suspicion on themselves.
- Several game shows have made use of this mechanic as an endgame, such as Friend or Foe, Golden Balls, and Take It All. In all three, a pair of contestants must choose to either share a jackpot, or take it for themselves. If one contestant chooses to take it, they take all the money and the other player gets nothing. If both choose to take it, they both walk away with nothing. Of the examples, all of them used this as an endgame, in combination with a system that eliminated players throughout the game. Friend or Foe however, did this once to every team throughout the game, either after they were eliminated (as a Consolation Prize), and once more with the winners at the end of the show (as the second half of a Bonus Round).
- In an episode of The Commish Tony uses the dilemma to trap a couple of killers. He has them brought in and kept for hours without food or drink. He explains the dilemma to one, who won't talk, so Tony lets him go. Then he has the DA go into the other holding room and offer the second guy whatever food he wants. The first guy sees the second guy through the office window, with the DA frantically scribbling down what he's saying, and thinks that the second guy is ratting him out, so the first guy blames the second one for the actual murder.
- Midsomer Murders: Barnaby uses the trope in one episode to get two individual murderers not to confess, but to witness that they saw the other committing a murder.
- In the Quantico episode "Cover", FBI Academy Deputy Director Miranda Shaw uses a variant as a Secret Test of Character. After getting her FBI cadets pissed off at each other, she tells them that they are to vote for three candidates to be cut from the training program. Refuse to vote, and she cuts ten. Alex tries to get her classmates to abstain, but Simon chickens out. Truth is, Miranda wasn't planning to cut anyone: the correct response was to stick with each other regardless of personal feelings, and she gives Simon and the candidates about to follow his lead a What the Hell, Hero? speech and threatens him with expulsion if he makes another mistake like that.
- The Castle episode "The Double Down" unusually presents the dilemma from the interrogators' perspective. The team realizes that two seemingly unconnected murders were prearranged to be done by the person who had motive for the other murder, in order to provide airtight alibis for the one they would be suspected of. Unfortunately they don't have any hard evidence, so if both suspects keep mum they can't prove the theory. To solve it, Ryan and Esposito tell the weaker link while Castle and Beckett are interrogating him that his partner has already given him up to save his own skin, which convinces the bluffed suspect to confess.
- This was frequently invoked on Jeopardy! in situations where there is a tie for first place going into the Final Jeopardy! round. The two tied contestants have no choice but to bet either All or Nothing on the Final Jeopardy! clue, depending on how much they trust the other to bet $0. In the best-case scenario, both bet $0 and are declared co-champions regardless of whether they get Final Jeopardy! right or wrong; worst-case scenario is that they both zero out on an incorrect response and the third contestant wins (unless they too bet everything). However, since ties for first place (and hence the co-champion rule) were abolished at the start of Season 31, this can no longer be done without leading to a Tiebreaker clue.
- A variant of the game appears in The Talos Principle's expansion Road to Gehenna on the message board that you explore within the game world. This version is meant as a combination game and social experiment, and has somewhat unconventional rules: if both participants "betray", each earns two points. If both "co-operate", neither person earns any points. If one betrays and the other co-operates, the former receives one point and the latter three points. Whoever has the most points at the end of the round loses. In contrast to the original dilemma, the participants are able to communicate beforehand, making the game more about bluffing than principles. Because of the way the points are awarded, the only way to win is to convince the opponent to co-operate while you betray (after which point, both parties will sensibly betray until the game ends).
- In Knights of the Old Republic, a computer trying to determine if the Player Character is authorized to access it proposes a Prisoner's Dilemma scenario and asks the PC what they would do. In this case, betraying their companion is the "right" choice because it works out better for you no matter what the companion does, but the PC can reject the computer's moral vision and still gain access.
- One of the games in The Jackbox Party Pack 3, Trivia Murder Party, has a minigame based on this scenario called "Decisions, Decisions". The host leaves a pile of money for the people in the game to take. If at least one person takes the money, anyone who didn't take it dies. If everyone takes the money, everyone dies. The only scenario where everyone is kept alive is if absolutely nobody takes any money, but would you really trust your friends to cooperate with you, especially if it involves more than 2 people?
- This is present as a Mini-Game in Universal Paperclips where your paperclip Maximizer AI runs. The player doesn't pick one of the choices — instead, it chooses one of a variety of different strategies (such as a Greedy algorithm which tries to take the choice with the potential most points), pits all the strategies against each other in the dilemma scenario, and receives a resource depending on how well said strategy scored.
- A minor character in Baldur's Gate II will ask the Player Character how they would respond to a modified version where a pair of siblings are captured by a sadistic wizard in individual cells and each given the option of pressing a button in their cell or not. Pressing the button will kill you, while pressing it will not. If only one person presses the button, the other goes free, but if both or neither presses the button both die. Depending on your answer, the character will 'reward' you with a challenging but rewarding battle or a zero effort battle with no reward. Alternatively...
Minsc: This is silly, buttons is not how one escapes dungeons! I would smash the button, and rain down beatings on the wizard liberally for playing such a trick!
- This is the basis behind the Nonary Game: Ambidex Edition in Zero Escape: Virtue's Last Reward, and Phi spends about 3 minutes explaining the concept to Sigma. The object is to escape the facility with 9 Bracelet Points, and the only way to get BP is to vote at the end of each round either for or against the people whom you cleared the round with. If both sides vote "ally," then both gain 2 BP; if one side votes "betray" while the other votes "ally," then the betraying side gains 3 BP and the betrayed loses 2. If both decide to betray, then neither will gain any BP for that round (which becomes a problem since the door to escape can only open once, meaning someone who played smarter could reach 9 BP before you do). Failing to vote causes the system to automatically vote "ally" on your behalf, which would seem to be an easy solution — but both sides failing to vote results in death by lethal injection via the point-counting bracelets worn by the players (which also happens to be the punishment for dropping to 0 BP). Funnily enough, after finishing her explanation, Sigma concludes that they should vote to ally, and Phi instead insists on betraying.
- In Danganronpa: Trigger Happy Havoc, Celestia Ludenberg references the concept and uses the example of two countries building their military strength under fear of betrayal from the other to explain the School Life of Mutual Killing that the 15 students have been forced into (in which uniting together against The Mastermind would be ideal, but none can escape the possibility of someone cracking under the pressure of wanting to escape the school by choosing to kill someone else).
- Atomic Rockets has a whole lot of them gathered in one place here.
- This website lets people run a simulation of this game against a computer opponent that follows a pre-selected strategy. The most common strategy is called "Tit for Tat"; i.e. repeating the action your opponent did last round.
- The Evolution of Trust is an interactive version of this puzzle, with different 'AIs' and the potential for miscommunication added to the mix.
- This video has it as the main theme. A man, Luc, commits a murder and asks his friends to help him cover it up. Between the three, who can he trust? Mathieu the "Fuckboy", who would dump him for the nearest girl, Thomas the "Skinflint" who keeps track of every penny owed to him, or William the "Cheater", who cheats and manipulates at every game due to being obsessed with victory? The answer is: all of them. Of course, William is aware of the Dilemma and that they will likely face it, and decides to cheat - after all, if nobody rats anyone out, they'll be free men. So they pass off Mathieu, their strongest willed member for their weakest in the face of the assistant detective, Pierre. He tells them to NOT get their lawyer, and instead ask if the alleged rat called his lawyer before confessing, calling the lead detective's bluff. And in the event that Luc would denounce himself out of loyalty to the others, William gave him false coordinates and location for the location where they buried the corpse, which would render any confession false, null and void. At the end, William admits that the Prisoner's Dilemma is infallible due to the very premise of lack of communication between the suspects, which eventually leads them to betray each other. But what if there was a fifth person, Pierre the "Loyal" one, who joined the police and rose to assistant detective at William's behest, putting in place a system to communicate the fact that nobody talked - such as, say, smacking a prison door in anger?
- Uno: The Movie features five men playing a game of Uno that, thanks to a ridiculous set of house rules, lasts for over two and a half hours. After around the forty minutes or so, each of the guys just wants the game to end, and talk about cooperating with each other to do so. The problem is, they can't help but continue to screw each other over in the vain hope of winning.
Gavin: We all want to go home, but nobody wants to lose!
- The Adventure Zone has Trust or Forsake in The Suffering Game arc, which is this trope. But even when the heroes get the best outcome, they end up forsaking friendly people they had met earlier.
- Played for Laughs when the titular Dilbert is accused of a crime and offered a chance to confess for a lighter sentence. He cites The Prisoner's Dilemma by name and taunts the interrogator, pointing out that since he and all his co-workers are aware of it none of them will talk and they'll all go free. The interrogator just shrugs and opens the curtains, showing every single one of his co-workers all gleefully ratting on Dilbert. For bonus points, none of them actually committed a crime and they all know it; they just ratted out Dilbert because it's just that kind of show.