A prisoner’s dilemma cheat sheet

Because cooperation is hard.


Always Cooperate

If you haven’t seen Mars Attacks recently, it’s so good! And it happens to be a great illustration of how being too optimistic about cooperation can have painful results.

Poll for you to take at the end of this article:


Always Defect

Daleks were engineered to hate everything and to destroy everything that they hate.

❋ How Prisoner’s Dilemma works

Cooperate|Defect
Defect|Defect 
Cooperate|Cooperate
Always Defect vs Always Cooperate:
100% (D|C)
----------------------------------
= 500 points | 0 points

Tit For Tat

Tit For Tat vs Always Cooperate: 
100% (C|C) 
-------------------------------
= 300 points | 300 points
Tit for tat vs Always defect:
   1% (C|D) 
+ 99% (D|D)
-----------------------------
= 99 points | 104 points

❋ Multi-player strategies give the game a twist

Always Defect vs Tit For Tat 1:
   1% (D|C) : starts nice
+ 99% (D|D) : but quickly adjusts
-------------------------------
= 104 points | 99 points
Always Defect vs Tit For Tat 2:
   1% (D|C) : starts nice
+ 99% (D|D) : then quickly adjusts
-------------------------------
= 104 points | 99 points
Tit For Tat 1 vs Tit For Tat 2:
100% (C|C) : starts and remains nice
-------------------------------
= 300 points | 300 points
Always Defect: 208 pointsTit For Tat 1: 399 pointsTit For Tat 2: 399 points

❋ The optimal strategy dances around

Left: Always Cooperate plays everyone; Right: Grim Trigger plays everyone.

Prober

Photo by doc obee via Flickr, via 11 Ways People Greet Each Other Around the World.
Prober vs Always Cooperate: D|C, C|C, C|C = Play Always Defect
98% (D|C)
 2% (C|C)
---------------------------
= 496 points | 6 points
Prober vs Always Defect: D|D, C|D, C|D = Play Always Defect
98% (D|D)
 2% (C|D)
------------------------
= 98 points | 108 points
Prober vs Tit For Tat: D|C, C|D, C|C = Play Tit For Tat
 1% (D|C)
 1% (C|D)
98% (C|C)
----------------------
= 299 points | 299 points


❋ The power of secret handshakes

11 secret handshakes you and your bestie should learn (BuzzFeed)
Left: Milk Snake (not poisonous); Right: Coral Snake (poisonous)

How cooperation evolves


If aliens landed on Earth tomorrow, which strategy would you vote for the world’s leaders to use when interacting with them? Would you pick Always Cooperate? Tit For Tat? Grim Trigger? Prober? Or something else?

Choose wisely. 👇

Thinking is Hard

Where I write about writing a book about biases, reasoning, and the art of having more productive disagreements.

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Buster Benson

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Author of Why Are We Yelling?, a book about the art of productive disagreement. I run 750words.com. Previously product at Patreon, Slack, Twitter, and Amazon.

Thinking is Hard

Where I write about writing a book about biases, reasoning, and the art of having more productive disagreements.