THE
EVOLUTION
OF TRUST
playing time: 30 min • by nicky case, july 2017
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During World War I, peace broke out.
It was Christmas 1914 on the Western Front.
Despite strict orders not to chill out with the enemy, British
and German soldiers left their trenches, crossed No Man's Land,
and gathered together to bury their dead, to exchange gifts, to sing.
Meanwhile: it's 2017, the West has been at peace for decades, and
we're less trusting than ever. Fewer and fewer people say they trust their
governments, their media, or even each other. So here's our puzzle:
Why & when do friends become enemies?
or: Why & when do enemies become friends?
I think game theory can help explain our epidemic of distrust –
and how we can fix it! So, to understand all this...
you
cooperate
you
cheat
they
cooperate
they
cheat
you
↙
other player
↘
THE GAME OF TRUST
You have one choice.
In front of you is a machine: if you put a coin in the machine,
the other player gets three coins – and vice versa.
You both can either choose to COOPERATE (put in coin), or CHEAT (don't put in coin).
Let's say the other player cheats, and doesn't put in a coin.
What should you do?
Exactly! Why let that moocher mooch off of you?
Alas, turning the other cheek just gets you slapped!
If you cooperate & they cheat, you lose a coin while they gain three. (score: -1 vs +3) However, if you both cheat, neither of you gain or lose anything. (score: 0 vs 0) Therefore: you should CHEAT.
But let's say the other player cooperates, and puts in a coin.
What should you do now?
Wow, that's mean... and also the correct answer!
Sure, seems like the right thing to do... OR IS IT??
Because if you both cooperate, you both give up a coin to gain three. (score: +2 vs +2) But if you cheat & they cooperate, you gain three coins at their cost of one. (score: +3 vs -1) Therefore: you "should" still CHEAT.
And that's the dilemma of trust. You'd both be better off trusting each other, but trust leaves you vulnerable. But what happens if we can...
Now, let's play for real.
You'll be playing against 5 different opponents, each with their own "personality".
With each opponent, you'll play anywhere between 3 to 7 rounds.
Can you trust them? Or rather... can they trust you?
Choose your first, real move:
opponent: [X] of [Y]
your total score:
And your total score is...
which is, wow, actually impressively bad.
which, uh, could be worse!
which ain't bad!
which is pretty good!
which is perfect! Congrats you have too much time on your hands.
...i have no idea how you did that.
(the lowest & highest possible scores are 8 and 49, respectively)
So who were these strange characters you just played against?
COPYCAT: Hello! I start with Cooperate, and afterwards, I just copy whatever you did in the last round. Meow
ALWAYS CHEAT: the strong shall eat the weak
ALWAYS COOPERATE: Let's be best friends! <3
GRUDGER: Listen, pardner. I'll start cooperatin', and keep cooperation', but if y'all ever cheat me, I'LL CHEAT YOU BACK 'TIL THE END OF TARNATION.
DETECTIVE: First: I analyze you. I start: Cooperate, Cheat, Cooperate, Cooperate. If you cheat back, I'll act like Copycat. If you never cheat back, I'll act like Always Cheat, to exploit you. Elementary, my dear Watson.
It's tournament time!
Each character will now play against every other character:
that's 10 paired matches, and 10 rounds per match.
Who do you think will get the highest total score?
Think carefully about it, and then
PLACE YOUR BETS:
Alright, you placed your bet on [CHAR]! Let's go through the matches one by one, and see how the tournament plays out...
first match →
next match →
Match #[N]: [A] vs [B]
Rounds:
Total Scores: [A] vs [B]
Oh, by the way...
[trench live & let live stuff]
[trench live & let live stuff]
[trench live & let live stuff]
[trench live & let live stuff]
[trench live & let live stuff]
[trench live & let live stuff]
[trench live & let live stuff]
Anyway -- and the winner is...
(drumroll please...) →
COPYCAT!
Congrats, you placed your bet on the right horse.
(Sorry, [CHAR].)
Copycat goes by many names.
The Golden Rule, reciprocal altruism, tit for tat, or... live and let live.
That's why "peace" could emerge in the trenches of World War I:
when you're forced to play the same game with the
same specific people (not just the same generic "enemy") over and over again --
Copycat doesn't just win the battle, it wins the war.
But if things change a lot when you play multiple rounds of the same game, what if we play...
Now, let's let our population of players evolve over time. It's a 3-step dance:
1. PLAY A TOURNAMENT
Let them all play against each other, and tally up their scores.
2. ELIMINATE LOSERS
Get rid of the 5 worst players. (if there's a tie, pick randomly between them)
3. REPRODUCE WINNERS
Clone the 5 best players. (if there's a tie, pick randomly between them)
Say we start with the following population of players:
15 Always Cooperates,
5 Always Cheats, and
5 Copycats.
(We'll ignore Grudger & Detective for now)
We're going to do the tournament-eliminate-reproduce dance a dozen times or so.
Let's make another bet! Who do you think will win the first tournament?
Makes sense, Always Cooperate outnumbers everyone else right now...
Makes sense, Always Cheat has a lot of Always Cooperates to exploit...
Makes sense, Copycat won the tournament last time, why not again?...
Let's see if you're correct:
1) play tournament
2) eliminate bottom 5
3) reproduce top 5
Alas, Always Cooperate got eaten up by Always Cheat, whose numbers have now increased by 5.
Sadly, you were correct! The Always Cheaters won this time, and their numbers increased by 5.
Alas, Copycat did not win – but at least they didn't do as bad as Always Cooperate, who got eaten up by Always Cheat, whose numbers have now increased by 5.
But let's try a few more rounds of this...
Always Cheat is still growing, at the expense of Always Cooperate...
And now, all the Always Cooperates are dead. But, wait...
That's right: the Always Cheats became a victim of their own success! They exploited the naive Always Cooperaters, but once they ran out of them, they had to face the Copycats: who are nice, but not naive.
By simply copying the other player's moves, Copycats can play nice with each other, while Always Cheats just cheat themselves. Not only that, but it also means Copycat can give Always Cheat a taste of their own medicine.
And so, as a result...
...Copycat inherits the earth.
So, although your bet was off -- the nice-but-naive Always Cooperaters were doomed from the start -- in the end, a smart form of niceness prevailed, and the Always Cheaters were squashed.
So, in the short run you were right - Always Cheat won the first few rounds, but in the end, its exploitativeness was its downfall.
So, in the long run, you were right - Copycat wins! Always Cheat may have won in the short run, but its exploitativeness was its downfall.
This reminds me of a quote:
"We are punished by our sins, not for them."
~ Elbert Hubbard
(oh, and by the way...)
(...this result is similar even if we put Grudger & Detective back in:)
start the evolution process!
stop the evolution process
(Note: occasionally, a few Grudgers may stick around,
because when all players except Grudger & Copycat
are eliminated, the two tie.)
So, it seems the math of game theory is telling us something:
that Copycat's philosophy,
"Do unto others as you would have them do unto you", may be not just a
moral truth, but also a mathematical truth.
However...
...there's a problem: →
There are jerks. Look around.
If Copycat is the strategy in this repeated game of trust that's so powerful --
that even soldiers in World War I trenches independently "evolved" a similar strategy, called "live and let live" --
why, then, are there so many un-trusting, un-trustworthy people?
What's causing our epidemic of un-trust?
A clue's in that sentence itself. "In this repeated game of trust."
So far we've only talked about change in the players:
what about a change in the game?
What could lead to...
...the evolution of distrust?
Before everything goes to heck, let's start with something nice!
Here's a world filled entirely with Always Cooperates,
except for one Always Cheat and one Copycat.
Use the buttons on the right to start the sim,
go through it step-by-step, or reset it. →
As you already know, Copycat wins handily in the long run,
under our current rules!
But that's under our current rules, which say that
players play against each other for 10 rounds per match.
Does Copycat still win at 7 rounds? 5 rounds? 3? 2? 1?
Change the number of rounds with the slider below,
start the sim, and see what happens.
Feel free to experiment as much as you'd like!
once you're done playing around, click:
As you saw, when people play below some number of rounds,
ALWAYS CHEAT dominates.
In 1985, when Americans were asked how many close friends they had,
the most common answer was "three". In 2004, the most common answer was "zero".
We now have fewer friends across class, racial, economic, and political lines,
because we have fewer friends -- period.
And as you just discovered for yourself,
the fewer "repeat interactions" there are, the more distrust will spread.
(no, mass media doesn't count:
it must be two-way interactions between specific individuals.)
and oh, it gets worse... →
There's another way to breed distrust. Here are the "payoffs" for the trust game:
Let's start with a mostly-Copycat world. Normally, they'd win. But now, change the "trust" reward from +2 to +1, then click start. → Even though +1 is still more than the punishment for mutual distrust (0)... what happens?
feel free to play around with different payoffs! once you're done, click:
(simulating: 10 rounds per match)
The same thing happens: Always Cheat dominates.
So even if the reward for getting a "win-win" is still more
than the punishment for a "lose-lose"...
if the reward for mutual trust is too low, distrust evolves.
I think, as a culture, we're losing the value of finding "win-wins".
We're more interested in "win-lose", because viciousness gets views, conflict gets clicks.
It's live and let die.
Maybe I'm just overthinking things, maybe I'm just old and shaking my fist at a cloud...
but don't you feel it? That we've forgotten something?...
...whatevs i dunno →
Aaaaanyway, now you can change both rules! (click start to see how, with weird payoffs, the sim "swings" between Cheats & Cooperates...)
Once you're done experimenting with this, let's look at our final barrier to trust...
Misteaks Mistakes. →
As cool as Copycat is, it has a huge, fatal weakness I haven't mentioned yet. To understand it, let's say two Copycats are playing against each other:
Being "nice" players, both their first moves will be:
And normally, they'd just pay back each others' kindness and sing Kumbaya until the end of time.
But what if, while trying to reciprocate...
OH NO
Mistakes, miscommunication, misinterpretations -- accidents happen all the time in real life.
But if the other person doesn't think it was an accident...
OH NO AGAIN
The other player, being a Copycat, had to retaliate...
...and you, being a Copycat as well, will also have to retaliate...
Thus, like the Hatfields and McCoys, these two Copycats will spiral into an endless cycle of vengeance... that started over a single mistake, long, long ago.
Tragic. But now, are there other types of players who can...
...deal with mistakes? →
Let's meet some new faces!
COPYKITTEN:
Hello! I'm like Copycat,
except I Cheat back only after you Cheat me twice in a row.
After all, the first one could be a mistake! Purrrrr
SIMPLETON:
hi i try start cooperate.
if you cooperate back, i do same thing as last move, even if it mistake.
if you cheat back, i do opposite thing as last move, even if it mistake.
RANDOM:
Monkey robot! Ninja pizza tacos! lol i'm so random
(Just plays Cheat or Cooperate randomly with a 50/50 chance)
Alright, let's see how well these peeps do when they...
...play in a tournament →
Noise Evolution, place your bets. At 5% noise
Try it, controls to the left
Simpleton wins, but let's try...
...different scenario, place your bets again.
Try it, controls to the left, again
Ooh, surprising... but is that true if there's a LOT of noise?
GIVE A SLIDER FOR NOISE.
Explain nonlinear barrier, and real life. Also sandbox.
Explain nonlinear barrier, and real life. Also sandbox.
Teaser for sandbox
Start off with this distribution of players:
The payoffs in a one-on-one game are:
set default
Play [N] rounds per match:
Play [N] round per match:
After each tournament, eliminate the bottom [N] players & reproduce the top [N] players:
After each tournament, eliminate the bottom [N] player & reproduce the top [N] player:
During each round, there's a [N]% chance a player makes a mistake:
...once you're done playing around, let's recap
what we've learnt →
TRUST: - repeated interaction: - win-win: - dealing with mistakes: forgive, and try to be clear and honest yourself DISTRUST: - loss of social capital - win-lose, use versus them, zero-sum - gleefully punishing even small mistakes But above all, there's also...
...the bigger lesson →
Don't hate the player, hate the game.
Game theory lesson.
Short term: game changes players. But don't be cynical
Long term: players change game, from the bottom up -- evolution.
So if we wanna cure our epidemic of distrust,
and rebuild a trusting & trustworthy civic society, it's up to all of us.
Let's all learn and act to find win-wins,
to create repeated interactions,
(and...)
...to live and let live.
Copycat
copycat
Copycat
Always Cheat
cheater
All Cheat
Always Cooperate
cooperater
All Cooperate
Grudger
grudger
Grudger
Detective
detective
Detective
Copykitten
copykitten
Copykitten
Simpleton
simpleton
Simpleton
Random
random
Random
cooperate
cheat
play
start
stop
step
reset
population
payoffs
rules
next →
continue
0. Introduction
1. One Game
2. Repeated Game
3. One Tournament
4. Repeated Tournament
5. The Evolution of Distrust
6. Making Mistaeks
7. Sandbox Mode
8. Conclusion
9. Credits