The Story So Far…
Two players are presented with an opportunity.  Each may remain loyal to the other player and betray him. Neither player will interact with the other in any way ever again. There is no out-of-game way to be rewarded and punished.

What could happen?

(1) If both remain loyal, each of them gets the “Cooperation” reward.

(2) If both betray the other, each of them gets the “Betrayal” reward.

(3) If one betrays the other while the other remains loyal, the betrayer gets the “Traitor” reward while the loyal one gets the “Sucker” reward.

This is the prisoner’s dilemma.

In a strict prisoner’s dilemma, the rewards are staggered with the “Traitor” reward best, followed by the “Cooperation” reward, then “Betrayal,” and finally “Sucker” the worst.  In mathematical terms, T > C > B > S.  My instincts as a designer suggest that we should also aim for 2C > T + S > 2B.

Further, We can encourage cooperation or betrayal among our players. Cooperation is more likely when this decision point occurs repeatedly but an uncertain number of times. Betrayal is more likely when this decision point occurs once and without any in-game opportunity for reprisal.

 

Including The Prisoner’s Dilemma In Game Designs

We have invested three columns to getting very familiar with the prisoner’s dilemma.  We looked at the research surrounding it and the mathematical theories applied to it.  Now let’s look at how this dilemma might be applied to our game designs.  Each of these is presented as a single case study.  You will of course need to adjust them to serve your particular needs.

 

Retrofitting  Munchkin

One fun way to get a sense of the prisoner’s dilemma in a game is to slip it into the classic back-stabber Munchkin.

A player has drawn a monster to fight.  The other players may play cards to boost the player and boost the monster.  Let’s have each of these other players simultaneously choose who to support–Hero or Monster.  Players that choose Hero are committed to playing cards for the active player.

(1) If the active player defeats the monster, that player gains one level but must give all monster loot away to the Hero players.

(2) If the monster defeats the active player, that player gets all the normal penalties.  The Monster players divvy up the monster’s loot among themselves.

 

An Area Control Game

There are 20 areas to be scored.  The order in which they are scored is randomized in a deck of cards.  Shuffled among the last 6 cards is an “End of Game” card.  When this card is revealed, the game is instantly over so it is likely that some areas will not score.

Any time two players are tied, they simultaneously select and reveal “Share” or “Steal.”

(1) If both players Share, each receives half (round up) of the victory points + 1 bonus VP.

(2) If both players Steal, each receives 1 victory point.

(3) If one player Shares while the other player Steals, the Stealing player gets all the each victory point and the Sharing player receives none.

 

A Civilization Game

It is the dawn of civilization.  Two hunting/gathering groups meet in neutral territory.  Each player simultaneously selects and reveals “Peace” or “War.”

(1) If both players choose Peace, each may exchange knowledge and/or goods.

(2) If both players choose War, units damage one another with the victor carrying away a fraction of their combined goods.

(3) If one player chooses Peace while the other player chooses War, the warrior annihilates the opposing player’s group and takes any goods the peaceful group was carrying.

 

A Political Game

Several players are competing for position in a campaign.  Each player must decide with respect to each opponent whether to run an Upbeat campaign or to run a Smear campaign.

(1) If both candidates are Upbeat, each gains 5 votes.

(2) If both candidates Smear, each candidate gains 2 votes.

(3) If one candidate is Upbeat while the other candidate Smears, the smear candidate gains 6 votes while the upbeat candidate gains 1.

 

A Racing Game
Two cars are approaching a bottleneck at speed 4.  Both cannot fit through at the same time.  Each will have to decide whether to “Accelerate” or “Brake.”

(1) If both cars Brake, they squeeze through the bottleneck at speed 3.

(2) If both cars Accelerate, they will crash in the bottleneck at speed 5!

(3) If one car Accelerates while the other car Brakes, the accelerating car pulls ahead to speed 5 while the braking car comes through at speed 2.

 

A Contribution From An Esteemed Reader

Bruno Faidutti mentioned in the comment section of Part 2 of this series that “[his] game Terra is based on the freerider paradox which can be considered a multiplayer generalization of the prisonner’s (sic) dilemma.”  I was only passingly familiar with the freerider paradox and decided to research it further.  The Stanford Encyclopedia of Philosophy offers a solid an overview.

Although I haven’t personally played Terra, it is clear how the freerider paradox could be quite an interesting basis for a game.  My first thought was how it might interact with the Peace War Game we discussed in part 2 of this series.  The freerider paradox will definitely get a full treatment from this blog sometime soon.  In the meantime, be sure to read the article at Stanford and try your hand at integrating it into one of your games.

 

Closing Thoughts

The prisoner’s dilemma mechanism can bring interplayer tension into a variety of settings.  It can be used to encourage collaboration.  It can be used to encourage competition.  It is a versatile device in your designer toolbox.

Have you played a game with a Friend and Foe mechanism? What did you think of it? Have you written one? How did your players respond to it?  Share with your fellow readers in the comments below.  And if you’re enjoying what you’re reading, create an account with WordPress and follow this blog.  You keep reading. I’ll keep writing.