Mafia (party game)
Mafia, also known as Werewolf, is a social deduction game created in 1986 by Dimitry Davidoff, then a psychology student at Moscow State University. The game models a conflict between two groups: an informed minority and an uninformed majority. At the start of the game, each player is secretly assigned a role affiliated with one of these teams. The game has two alternating phases: first, a night-phase, during which those with night-killing-powers may covertly kill other players, and second, a day-phase, in which all surviving players debate and vote to eliminate a suspect. The game continues until a faction achieves its win condition; for the village, this usually means eliminating the evil minority, while for the minority, this usually means reaching numerical parity with the village and eliminating any rival evil groups.
History
Dimitry Davidoff is generally acknowledged as the game's creator. He dates the first game of Mafia to spring 1987 at the Psychology Department of Moscow State University, from where it spread to the classrooms, dorms, and summer camps. Davidoff says that he brought Mafia into the Psychology department classrooms for research and it spread from there to dormitories and likely over next summer, through student summer camps. He credits this game-based methodology to pioneering 1920s psychologist Lev Vygotsky and the Turing test. He developed the game to combine psychology research with his duties teaching high school students. It became popular in other colleges and schools in the Soviet Union, often associated with hugely popular TV series La Piovra, which first ran in 1986. In the 1990s, it began to be played in other parts of Europe and then the United States. By the mid 1990s, a version of the game became a Latvian television series with a parliamentary setting, and played by Latvian celebrities.In 1997, the werewolf theme was added to the game by Andrew Plotkin, arguing that the mafia had less cultural resonance, and that the werewolf concept fit the idea of a hidden enemy who looked normal during the daytime.
The Werewolf variant of Mafia became widespread at major tech events, including the Game Developers Conference, ETech, Foo Camps, and South By Southwest. In 1998, the Kaliningrad Higher school of the Internal Affairs Ministry published the methodical textbook Nonverbal communications. Developing role-playing games 'Mafia' and 'Murderer' for a course on Visual psychodiagnostics, to teach reading body language and nonverbal signals. In September 1998, Mafia was introduced to the Graduate College at Princeton University, where several variants were developed. The werewolf theme was also incorporated in the French adaption of Mafia, The Werewolves of Millers Hollow.
In 2016, a film, Mafia: The Game of Survival was made in Russia based on the game; however, it received negative reviews.
Gameplay
In its simplest form, Mafia is played by two teams: the mafiosi and the villagers. Live games require a moderator who does not participate as a player, and identities are assigned by handing out cards, or by other non-verbal methods such as physically tapping players. At the start of the game, every mafioso is given the identities of their teammates, whereas the innocents only receive the number of mafiosi in the game.In an open setup, the numbers of each power role present in the game is known to the players, while in a closed setup, this information is not revealed, and in a semi-open setup, only limited or tentative information about the power roles is revealed.
There are two phases: night and day. At night, certain players secretly perform special actions; during day, players discuss and vote to eliminate one player. These phases alternate with each other until all mafiosi have been eliminated or they reach numerical parity with the innocents.
Some players may be given roles with special abilities. Common special roles include [|an investigative role], [|a protector role], and [|some association roles].
Andrew Plotkin recommends having exactly two mafiosi, whereas the original Davidoff rules suggest a third of the players be mafiosi. Davidoff's original game does not include roles with special abilities. In his rules for "Werewolf", Plotkin recommends that the first phase be night and that there be an odd number of players. These specifications avoid tie votes for eliminations and ensure that the game will end dramatically on an elimination rather than anticlimactically with murder as a foregone conclusion.
Night
All players are told to close their eyes. The moderator then instructs all mafiosi to open their eyes and acknowledge their accomplices via tap on the shoulder. The mafiosi pick a "victim" by silently gesturing to indicate their target and to show unanimity then close their eyes again.A similar process occurs for other roles with nightly actions. In the case of the seer, the moderator may indicate the target's innocence or guilt by using gestures such as nodding or head shaking. Night may be accompanied by players tapping gently to mask sounds made by gesturing.
Day
The moderator instructs players to open their eyes and announces who "died" the previous night. Discussion ensues among the living players. At any point, a player may accuse someone of being a mafioso and prompt others to vote to eliminate them. If over half of the players do so, the accused person is eliminated and night begins. Otherwise, the phase continues until an elimination occurs.According to some rules, the role of dead players should be revealed; according to others, for example, if the protector dies, nobody should know that. In both cases, dead players are not permitted to attempt to influence the remainder of the game.
Because players have more freedom to deliberate, days tend to be longer than nights.
Game theory
Mathematical study
Mafia is a complicated game to model, so most analyses of optimal play have assumed both that there are only townsfolk and Mafiosi and that the townsfolk never have a probability of identifying the Mafia that is better than chance. Early treatment of the game concentrated on simulation, while more recent studies have tried to derive closed-form equilibrium solutions for perfect play.In 2006, the computer scientists Braverman, Etesami and Mossel proved that without detectives and with perfect players the randomized strategy is optimal for both citizens and mafia. When there is a large enough number of players, to give both groups similar probability of winning, they showed that the initial number of mafiosi m needs to be proportional to the square root of the total number of players P, that is. With a simulation, they confirmed that 50 mafiosi would have almost a 50% chance to win among 10,000. The Mafia's chance of victory is
which is a good approximation when the right hand side is below 40%. If any detectives are added to the game, Braverman et al. proved that the number of Mafiosi must remain at a fixed proportion of the total number of players for their chance of winning to remain constant.
In 2008, Erlin Yao derived specific analytical bounds for the mafia's win probability when there are no detectives.
In a paper from 2010, the exact formula for the probability that the mafia wins was found. Moreover, it was shown that the parity of the initial number of players plays an important role. In particular, when the number of mafiosi is fixed and an odd player is added to the game, the mafia-winning chance do not drop but rise by a factor of approx. .
Results in live play
In live real-time play, the innocents typically win more often than game theory suggests. Several reasons for this have been advanced:- The physiological stress of sustained lying degrades the initial ability of mafioso to deceive the innocents, much more than a model of perfect play would predict, especially if the innocents can get the town emotionally involved in the game's outcome:
- The information revealed by the mafiosi voting patterns tells against them later in the game. One of the game's fans, Max Ventilla, has said that "If the villagers are allowed to keep a pencil and paper, they always win."
- As players get more experienced, their strategic sophistication and ability to spot and use deception increases. They will typically get better at the skills needed for playing innocents faster, being villagers more often than mafiosi.
- The Metagame aspect: Dimma Davidoff has said past connections will always lose to future collaborations. When playing several Mafia games with the same people, it's more helpful to be known for honesty than for deceit. Davidoff considers that so important that he thinks the advantages of playing the mafioso role honestly outweigh the disadvantages.
Optional roles
These additional roles are named differently in the many versions of Mafia, for thematic flavor, or historical reasons. Also, the same role-name can have differing functions across different versions of the game. What follows is a general list of role types found in Mafia variants; since the specific names vary by milieu it must be non-exhaustive.Investigative roles
Players with these roles use their own night-phase to discover something about other players. Though the standard game now includes the basic Detective, these roles are optional, and games can exclude them entirely.Investigative roles (standard)
Detective, Seer, Commandant, Sheriff, Police, etc.Investigative roles (less common)
Psychic, Wizard, Fortune Teller, Oracle, Tracker, Watcher, etc.Omniscient roles
Witness, Child, Little Girl, etc.Protective roles
Guardian Angel, Doctor, Bodyguard, Hero, Jailer, etc.Killing roles
Vigilante, Veteran, ''Hunter, Bomb, Woodcutter'', etc.Alignment roles
Miller, Godfather, Alpha Wolf, Wildcard, etc.Double-agent roles
Traitor, Possessed, Undercover Cop, Godfather, etc.Role manipulators
Role-blocker, Bus Driver, Thief, Barman, Witch, etc.Recruitment roles
Godfather, Psychiatrist, Piper, Cult Leader, etc.Association roles
Freemasons , Siblings, Lovers, Police, etc.Election roles
Doublevoter, Priest, Rabble Rouser, Lawyer, etc.Public roles
Mayor, Judge, Sheriff, President, etc.Handicapped roles
Drunk, Village Idiot, Teenage Werewolf, etc.Handicapper roles
Silencer, Dentist, Prostitute, Fog, etc.Post-mortem roles
Dark Background, Priest, Medium, Coroner, etc.Reanimation roles
Reviver, Governor, Martyr, Witch, etc.Rule-immune roles
Bulletproof, Oracle, Elder, etc.Special roles
Baker, chef, ''Village Idiot, Cobbler'', etc.Complicated roles
Additional variations exist, sometimes with even more specialized or complicated abilities. There are many special roles, and many moderators design novel roles for each game. Some commercial variants ship with blank cards to allow this customization. For example, neutral factions such as the serial killer could exist.Variations
The naming of various roles, factions, and other elements of play is theme-dependent and has limitless variation. Common alternative themes restyle the mafia as werewolves, cultists, assassins, or witches, with other roles being renamed appropriately.Over the years, players have created Mafia variants that include additional rules. Some of these are listed here.
Thing variant
In the variant called "Thing", the antagonists are Things, shape-shifting aliens that can turn humans into other Things.Variations on the win conditions
If there are as many mafiosi as innocents in the day-phase then a mafia victory is declared immediately, under the original Mafia rules. With the ability to deny a majority at an elimination vote, remaining mafiosi cannot be eliminated unless innocent/neutral killing roles exist. Other variants suspend this rule, and only declare the game after every member of one faction has been eliminated: this makes the game easier to explain, and to run.Election variants
Nominees for elimination may be allowed to make a speech in their own defense. Usually, each player must vote, can only vote once and cannot vote for themselves. But some variants have a more complicated process of selecting players to be executed. Davidoff's original 'Mafia' allowed multiple day-time executions, each needing only a plurality to action.Voting variants abound, but any elimination usually requires an absolute majority of the electorate, or votes cast. So the voting is usually not by secret ballot for multiple candidates with the highest vote count eliminated; it is more usual for the voting to be openly resolved either by:
- A nomination or series of elections structured to ultimately offer a choice between two candidates, or
- An option to eliminate one suspect.
Tied votes
Deadlocked elections can be resolved by lot or by killing the player with the scapegoat special role.The special case of one mafioso and one innocent remaining can be decided randomly or be ruled a Mafia win—this is more usual in live play.
Optional elimination variant
The Innocents can choose not to kill anybody during the day. Although commonly unsure of Mafia identities, the Innocents are more likely to randomly kill a mafioso than are the Mafia. Therefore, not eliminating anyone will typically favor the Mafia.However, when the number of survivors is even, No Kill may help the Innocents; for example, when three Innocents and one mafioso remain – voting for No elimination gives a 1/3 chance of killing the mafioso the next day, rather than a 1/4 chance today.
Mafia killing methods
Some variants require all Mafia members to choose the same victim independently for a kill to succeed. This can be achieved in the following ways:- By waking the Mafia members up separately.
- By calling out the names of all surviving players and requiring surviving mafiosi to raise their hands when the name of the victim is called out. In this variant, the mafiosi only "wake up" at the very beginning of the game when they identify each other. This variant also allows other roles to take their actions by simply raising their hands when their target's name is called out.
- By having them write their kills. Under this variant, Innocent players write the word 'honest' on a piece of paper; Mafia members write the name of a player for elimination. If all the mafia notes have the same name on them, that player is considered killed by the Mafia.
Another variant requires the night-time vote to be secret and unanimous, but allows multiple players to be added to the execution queue to ensure unanimity.
Multiple families
Multiple, independent groups of mafia or werewolves act and win independently, giving faster game-play and the potential for cross-fire between the factions.Attributes
In this variant, players are given two cards: the first contains their role, the second an attribute. Attributes were originally derived from roles that could apply to both Mafia and Innocent alignments such as Bulletproof, Mayor, and Siamese Twins.Quantum Werewolf
This variant was developed by Steven Irrgang and used for a puzzle in the 2008 CISRA Puzzle Competition. The difference from a standard game of Mafia is that players are not initially assigned roles, but rather on each day are given the probabilities describing the game's current quantum state. Each player with a non-zero probability of being a seer or a werewolf performs the appropriate night actions. When a player is killed, the wave function collapses and the players are given updated probabilities.Train Mafia
Traditional Mafia re-envisioned and heavily modified by the Copenhagen Game Collective to be played in a subway metro. In this variation, players who are eliminated are kicked off the train, and must wait in shame for the following train – a kind of 'afterlife' train – to join a second, interwoven game.Invisible City: Rebels vs. Spies
A location-based mobile gaming variant for Android, designed for city center play. The two factions are: the Rebels, the majority; and the Spies, the informed minority. The rule-set replaces expulsions with scoring by round. Each player is assigned an individual mission each round. Some missions are critical and if one of those fails, the round goes to the Spies, but only one player knows which missions are critical.Ultimate Werewolf
In this version of Mafia, the main enemies are the werewolves, as opposed to the mafia. The werewolves wake at night to kill a player, who is usually a Villager. Other helpful roles such as the Seer, Bodyguard, and Witch exist to help purge the village of werewolves, but other neutral roles exist such as the Tanner, lovers, and a third major faction: Vampires.One Night variant
In this standalone game published by Bezier Games, players only "sleep" and close their eyes for a single night at the beginning of the game. They then have a single day of discussion, with a single elimination. No players are eliminated as the game progresses. There is no moderator, so everyone gets to participate as a member of the town or village. When playing this game, three more role cards are used than the number of players; when everyone is randomly dealt out their card the three extra ones placed in the middle of the table. To begin the game one of the players, with eyes closed, will act as the "caller" on the single starting night, going through the nighttime roles once: Werewolves and Minions will identify each other, the Seer will examine one player's card or two of the middle cards, the Robber will steal another player's role card and replace it with their own, the Troublemaker will blindly swap two players' role cards, the Insomniac wakes up to check if their role card has been swapped, etc. The game ends on a single elimination vote, with the villagers winning if a single werewolf is caught, and the werewolves winning if no werewolves are killed. This game can be played with as few as three players. Play time can be as quick as five minutes per game.Town of Salem
Town of Salem is an advanced online version of Mafia that takes place during the Salem witch trials. It involves several different roles from multiple factions. The game was updated on 6 June 2017, to add a new faction: the Coven, which mainly consists of witches and is similar in function and goal to the more traditional Mafia.A sequel to the game, Town of Salem 2, was released on 26 May 2023, for release on Steam. The game removes the Mafia faction, but repurposes the function of most roles within the Mafia into the Coven. Gameplay remains similar to the original game.
Online play
Mafia can also be played online. Games can be played on IRC channels, where a bot assumes the role of a game moderator and the interaction of players is conducted via textual communication.Artificial intelligence
Werewolf is a subject of artificial intelligence research due to its unique features such as persuasion and deception. The game requires several AI technologies such as multi-agent coordination, intentional reading, and understanding of the theory of mind.Deep learning has been used in an attempt to develop agents that can win the game as werewolves or as villagers. Regular expressions have been used to parse utterance logs for divulgence and decision information, although one difficulty has been that a statement such as "Player A is a werewolf" could be based on either the player's ability or just speculation.