Portugues
The Evolution of Trust
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About the game
There is a machine with a slot for one coin. If you put a coin in, the other player gets three coins, and if they put one in, you get three. You can cooperate (put the coin in) or cheat (keep it). If you both cooperate you both come out ahead; if one cheats, the cheater wins; if both cheat, nobody gains. That is the prisoner's dilemma, and it is the starting point for the whole guide.
From there The Evolution of Trust turns into a short course taught through play. You meet the same stranger again and again and learn what a repeated game does to the logic. You play against a cast of characters with simple strategies, such as Copycat, Always Cooperate and Always Cheat, then see them compete in a tournament and in an evolving population where the winners multiply. You also see what miscommunication does to the strategies, and in the sandbox at the end you can build your own contest. The tone is light and the drawings are friendly, but the ideas come from real research, notably Robert Axelrod's work on cooperation.
Nicky Case made it in 2017 as an "explorable explanation": a lesson where the reader can touch the model.
Playing it here
Click Play now and then the arrow button. Read each screen, make your choice and move on. The circles along the bottom show the sections and let you jump back or ahead. Sound can be turned off with the speaker icon. Nothing is saved, so give it about thirty minutes.
A few things worth knowing
It is not only about one lesson. The final sections show that the same characters can win or lose depending on the rewards and on how often people misread each other, so try the sandbox with different settings.
Some sounds are missing. A few sound effects (the buttons, the scratching and the slot machine) were left out, because their licences are not free enough for this site; the game works without them.
Credits and licence
Created by Nicky Case and dedicated to the public domain under Creative Commons Zero. The music is Bleu by Komiku (CC0) and several sound effects come from Freesound users under CC0. The game uses PIXI.js and Howler.js (MIT), Tween.js, Q, MinPubSub, Pegasus and Balloon.css, and the font Patrick Hand (SIL OFL 1.1) in place of the original one. The licence texts are linked from this page.