
The Farmer's Dilemma - philh
http://reasonableapproximation.net/2015/05/05/farmers-dilemma.html
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AndrewOMartin
This seems to make the same assumption as analysis of the prisoner's dilemma.
That is that it's an isolated decision. If you take the decision into any kind
of realistic context, you'd never say something as cold as "I'm sure you'd do
it anyway" (similar to defecting in the case of the Prisoner's Dilemma) as any
reasonable analysis will show it to be suboptimal.

I've often encountered thought experiments like this with a moral along the
lines of "Some times it pays to be bad, it's upsetting, but it's the truth and
here's the maths that proves it" but it's always been equally interpretable as
"look how bad a job naive game theory does at explaining real life".

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dredmorbius
Iterated prisoners dilemma.

The interesting developments start appearing toward the end of a finite set of
iterations. How long do you _keep_ cooperating? Who defects first?

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gohrt
[http://en.wikipedia.org/wiki/Chainstore_paradox](http://en.wikipedia.org/wiki/Chainstore_paradox)

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dredmorbius
I'm not following that at all. But thanks.

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vinceguidry
How about this resolution: "Ah. Okay, so it's like that. Tell you what, why
don't you mull it over and I'll come ask you about it again next year." You
were getting by just fine without it before, you'll get by fine without it
even after you know about it. No need to burn any crops, just make your case a
little better next year, be a little less cooperative come harvest time, and
he'll get the picture eventually.

Game theorists always seem to assume that there's no such thing as nuanced
communication.

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fiatmoney
Repeated games are definitely a fixture of game theory. And given repeated
games, the notion of signalling comes heavily into play.

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YokoZar
The Farmer's Dilemma is very clearly the same as the Public Goods Problem:
[http://en.wikipedia.org/wiki/Public_good](http://en.wikipedia.org/wiki/Public_good)

Specifically, public goods are goods where there is a temptation to free ride.
As illustrated in the article, this doesn't always mean 0 public goods get
made even by perfectly rational actors -- sometimes it's worth it for someone
to do it anyway (Imagine putting up a street light in front of your shop if
your local government didn't do it for you.)

The Wikipedia page has dozens of possible solutions, both economic and social
-- everything from government provision to buying out possible free riders to
subsidies to social sanctions.

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baddox
It's actually a special case of the public good problem. Most public goods
aren't worth more to one individual than it would cost that individual to
produce. A strong military defense for my country is a classic example of a
public good, but it probably costs way more than it is worth to me. Yet it's
still a public good because it is worth more to the entire country than it
costs to produce.

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erikpukinskis
My personal favorite: Throw in a little extra to bring them over the top in
their utility calculation.

"Tell you what. Go halfsies on this ditch thing with me and I'll bring over a
half a pig to throw in your freezer in October."

You reduce your workload by half and you only give up 1.1 utilon. You get 1.9
utilons for 1 (1.9x efficiency) vs getting 3 for 2, which is only 1.5x
efficiency.

If you have plenty of good work lined up, that's the better way to go. You'd
only dig it yourself if you had a lot of free time.

Plus if you offer them something you produce yourself, you can get half of it
back as profits. I.e. the foreign aid approach.

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bcx
There is an interesting metaphor here of how B2B integrations are similar to a
farmer's dilemma. Two B2B companies talk about doing an integration. Both will
benefit if it is done, but one generally does more of the work.

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raldi
Jerry Yang and Steve Ballmer once played a variant of this game.

Both lost.

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screature2
Hmm... your "Farmer's Dilemma" description makes me want to call this a Free-
Rider Problem, but that doesn't quite seem to be equivalent

Maybe it's that you're about contemplating incentive structures underlying the
_creation_ of a public good rather than the traditional Tragedy of the Commons
_maintenance_ of a public good?

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dredmorbius
No, that's correct.

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dredmorbius
In the specific construct of this example, another option would be for the
farmer who digs the ditch to alter its placement such that it doesn't provide
a benefit to his neighbor.

Rather than run the ditch between the properties, he could run it down the far
side of his own, or the center, for that matter.

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yellowapple
> But in the real world, two people crashing their cars into each other is a
> worse outcome than two people failing to dig a ditch.

Wrong. By failing to dig the ditch, rainwater will now flood your properties,
ruining both cars.

:)

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im3w1l
> Maybe I have a bad back, and digging is more costly for me than for you.
> This may or may not change the Nash equilibria, and it may or may not change
> the amount of sympathy we each get in the various continuations.

And this is why money is nice. Because it enables the outcome with greatest
total utility in this case: that the healthy guy digs the ditch by himself and
gets a promise of future reward.

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dredmorbius
You don't need money for that to happen though. Just a system of credit (or
other enforced obligations), and a generally agreed on exchange rate.

Curiously enough, the subject of a great many of the earliest legal codices.

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chrismealy
Is this the stag hunt / assurance game? I'm too lazy too lazy to do the math
right now.

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philh
No, that has quite a different structure.

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hayd
I thought they were going to extend the analogy to contributing to open source
software...

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VT_Drew
When did the "Prisoners Dilemma" get renamed to the "Farmers Dilemma"?

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dragonwriter
The article references the Prisoner's Dilemma and notes that they are
different and have different Nash equilibria. The structure is different.

Giving the strategy of the actor whose payoff is considered first and the
other actors second, the order of payoffs for FD is:

D/C => C/C => C/D => D/D

The payoffs for PD are:

D/C => C/C => D/D => C/D

PD has a dominant strategy of defection because _independent_ of the other
player's strategy, you always get a better result by defecting.

FD lacks a dominant strategy because whether a particular strategy improves
your expected payoff depends on the other player's strategy.

