A short note to start the review that the author isn’t happy with how it is communicated. I agree it could be clearer and this is the reason I’m scoring this 4 instead of 9. The actual content seems very useful to me.
AllAmericanBreakfast has already reviewed this from a theoretical point of view but I wanted to look at it from a practical standpoint.
***
To test whether the conclusions of this post were true in practice I decided to take 5 examples from the Wikipedia page on the Prisoner’s dilemma and see if they were better modeled by Stag Hunt or Schelling Pub:
Climate negotiations
Relationships
Marketing
Doping in sport
Cold war nuclear arms race
Detailed analysis of each is at the bottom of the review.
Of these 5, 3 (Climate, Relationships, Arms race) seem to me to be very well modeled by Schelling Pub.
Due to the constraints on communication allowed between rival companies it is difficult to see marketing (where more advertising = defect) as a Schelling Pub game. There probably is an underlying structure which looks a bit like Schelling Pub but it is very hard to move between Nash Equilibria. As a result I would say that Prisoner’s Dilemma is a more natural model for marketing.
The choice of whether to dope in sport is probably best modeled as a Prisoner’s dilemma with an enforcing authority which punishes defection. As a result, I don’t think any of the 3 games are a particularly good model for any individual’s choice. However, negotiations on setting up the enforcing authority and the rules under which it operates are more like Schelling Pub. Originally I thought this should maybe count as half a point for the post but thinking about it further I would say this is actually a very strong example of what the post is talking about – if your individual choice looks like a Prisoner’s Dilemma then look for ways to make it into a Schelling Pub. If this involves setting up a central enforcement agency then negotiate to make that happen.
So I’m scoring it 4 out of 5 Prisoners Dilemmas examined are better modeled as Schelling Pubs, which is in line with the “most” claims of the post title.
The example which was least like Schelling Pub was the one where communication was difficult/impossible due to external rules. I think the value of communication is implicit in the post but it would be helpful to have it spelled out explicitly.
One other thing which might be useful from a practical point is that things which don’t initially seem iterated may be able to be iterated if you split them into smaller tasks. You don’t have to reduce your nuclear arsenal or decarbonise all at once, you can do a little bit and then check that the others have done the same before continuing. This seems obvious on a national level but maybe not so obvious on a personal level.
***
(Read beyond here only if you’re interested in more detail of the examples—it doesn’t add to the conclusions)
Below is my analysis of the 5 items chosen from the Prisoner’s dilemmas example list on Wikipedia. In discussing Stag Hunts (SH) I use the post’s list of 4 items which might make something more like a SH than a Prisoner’s Dilemma (PD).
Climate negotiations
PD shaped
Each country benefits from stable climate
Each would prefer that they put in minimum effort to achieve it
SH shaped?
Iteration: Yes—it is iterated over years and agreements
Reputation: It seems like yes, although I’m not sure how this works out in practice
Enforecable contracts: Not really
Superrationality: Possibly
SP shaped?
It seems yes.
As an example, recall the coal amendment from the Glasgow talks
This is an amendment which favours some countries over others and means that those disfavoured will put in relatively more effort for a given amount of CO2 reduction compared to the original wording.
It seems obvious that the actual agreement probably isn’t on the Pareto frontier
I think the final figure from the post gives a good mental model of what is going on
Relationships
PD shaped
In theory, for an individual action, you’re better off if you get your own way over your partner
SH shaped?
Iteration: Yes (+ your partner can just leave)
Reputation: Very important in small communities, less so in large ones
Enforceable contracts: Sometimes (prenup)
Superrationality: Potentially yes but not required
It will be better to hunt stag together just from iteration
Abusive relationships are not SH shaped as the partner can’t or won’t leave, especially when there’s no reputational effect that the abusive partner cares about
2 rival companies with equally effective marketing departments are in a roughly PD shaped game (assuming customer pool is fixed size)
If one spends money on advertising (defect) then the other is disadvantaged if they don’t
But both would be better off if neither advertised
Often the customer pool is not of fixed size which would mean that this may not really be a PD in real life
It is important here to note that collusion between companies is generally forbidden so communication is not allowed
SH shaped?
Iteration: Yes.
Reputation: Not really – there aren’t negative reputation effects to advertising
Enforceable contracts: No
Modelling other players: Yes but they are (accurately) modelling each other as playing defect
In theory the businesses could get into C-C but advertising is so ingrained as the default choice that this would be hard
Possibly there’s an availability heuristic problem here – I’ll obviously remember the examples of industries which are stuck in D-D as I constantly see their adverts (Pepsi vs Coke, tech companies, supermarkets).
I tried to think of industries that aren’t advertising much but I’m drawing a blank.
SP shaped?
In theory maybe, however the lack of communication makes it extremely hard for companies to change between solutions
Doping in sport
PD shaped
Using drugs gives you an edge but has a price potential price with medical dangers
There is a potential difference from “standard” PD in that doping is disadvantageous to a more able athlete if the less able athlete is not doping (which would make this an alibi game).
SH shaped?
Iteration: Yes (although results of previous iterations are not very legible)
Reputation: Yes (again, legibility problems)
Enforceable contract: Yes – drugs testing and bans
Superrationality: No
The enforceable contract is probably the biggest effect here – just relying on iteration and reputation would be insufficient
SP shaped?
Because the solution is an enforceable contract the decision is not very SP shaped on an individual basis
Negotiating what the contract should be is SP shaped
Reputation: A bit but probably not in a relevant way
Enforceable contract: Not really – if one country reneged then it’s not like the other country could sue
Superrationality: Yes. It seems both players realised D-D was terrible and wanted to play C-C. They couldn’t rely on just this so iteration was very important.
SP shaped?
Deciding the terms of the agreement is SP shaped
What size arsenal is better for which country?
Which particular weapons are better for which country?
A short note to start the review that the author isn’t happy with how it is communicated. I agree it could be clearer and this is the reason I’m scoring this 4 instead of 9. The actual content seems very useful to me.
AllAmericanBreakfast has already reviewed this from a theoretical point of view but I wanted to look at it from a practical standpoint.
***
To test whether the conclusions of this post were true in practice I decided to take 5 examples from the Wikipedia page on the Prisoner’s dilemma and see if they were better modeled by Stag Hunt or Schelling Pub:
Climate negotiations
Relationships
Marketing
Doping in sport
Cold war nuclear arms race
Detailed analysis of each is at the bottom of the review.
Of these 5, 3 (Climate, Relationships, Arms race) seem to me to be very well modeled by Schelling Pub.
Due to the constraints on communication allowed between rival companies it is difficult to see marketing (where more advertising = defect) as a Schelling Pub game. There probably is an underlying structure which looks a bit like Schelling Pub but it is very hard to move between Nash Equilibria. As a result I would say that Prisoner’s Dilemma is a more natural model for marketing.
The choice of whether to dope in sport is probably best modeled as a Prisoner’s dilemma with an enforcing authority which punishes defection. As a result, I don’t think any of the 3 games are a particularly good model for any individual’s choice. However, negotiations on setting up the enforcing authority and the rules under which it operates are more like Schelling Pub. Originally I thought this should maybe count as half a point for the post but thinking about it further I would say this is actually a very strong example of what the post is talking about – if your individual choice looks like a Prisoner’s Dilemma then look for ways to make it into a Schelling Pub. If this involves setting up a central enforcement agency then negotiate to make that happen.
So I’m scoring it 4 out of 5 Prisoners Dilemmas examined are better modeled as Schelling Pubs, which is in line with the “most” claims of the post title.
The example which was least like Schelling Pub was the one where communication was difficult/impossible due to external rules. I think the value of communication is implicit in the post but it would be helpful to have it spelled out explicitly.
One other thing which might be useful from a practical point is that things which don’t initially seem iterated may be able to be iterated if you split them into smaller tasks. You don’t have to reduce your nuclear arsenal or decarbonise all at once, you can do a little bit and then check that the others have done the same before continuing. This seems obvious on a national level but maybe not so obvious on a personal level.
***
(Read beyond here only if you’re interested in more detail of the examples—it doesn’t add to the conclusions)
Below is my analysis of the 5 items chosen from the Prisoner’s dilemmas example list on Wikipedia. In discussing Stag Hunts (SH) I use the post’s list of 4 items which might make something more like a SH than a Prisoner’s Dilemma (PD).
Climate negotiations
PD shaped
Each country benefits from stable climate
Each would prefer that they put in minimum effort to achieve it
SH shaped?
Iteration: Yes—it is iterated over years and agreements
Reputation: It seems like yes, although I’m not sure how this works out in practice
Enforecable contracts: Not really
Superrationality: Possibly
SP shaped?
It seems yes.
As an example, recall the coal amendment from the Glasgow talks
This is an amendment which favours some countries over others and means that those disfavoured will put in relatively more effort for a given amount of CO2 reduction compared to the original wording.
It seems obvious that the actual agreement probably isn’t on the Pareto frontier
I think the final figure from the post gives a good mental model of what is going on
Relationships
PD shaped
In theory, for an individual action, you’re better off if you get your own way over your partner
SH shaped?
Iteration: Yes (+ your partner can just leave)
Reputation: Very important in small communities, less so in large ones
Enforceable contracts: Sometimes (prenup)
Superrationality: Potentially yes but not required
It will be better to hunt stag together just from iteration
Abusive relationships are not SH shaped as the partner can’t or won’t leave, especially when there’s no reputational effect that the abusive partner cares about
SP shaped?
Ideally.
Marketing
PD shaped
2 rival companies with equally effective marketing departments are in a roughly PD shaped game (assuming customer pool is fixed size)
If one spends money on advertising (defect) then the other is disadvantaged if they don’t
But both would be better off if neither advertised
Often the customer pool is not of fixed size which would mean that this may not really be a PD in real life
It is important here to note that collusion between companies is generally forbidden so communication is not allowed
SH shaped?
Iteration: Yes.
Reputation: Not really – there aren’t negative reputation effects to advertising
Enforceable contracts: No
Modelling other players: Yes but they are (accurately) modelling each other as playing defect
In theory the businesses could get into C-C but advertising is so ingrained as the default choice that this would be hard
Possibly there’s an availability heuristic problem here – I’ll obviously remember the examples of industries which are stuck in D-D as I constantly see their adverts (Pepsi vs Coke, tech companies, supermarkets).
I tried to think of industries that aren’t advertising much but I’m drawing a blank.
SP shaped?
In theory maybe, however the lack of communication makes it extremely hard for companies to change between solutions
Doping in sport
PD shaped
Using drugs gives you an edge but has a price potential price with medical dangers
There is a potential difference from “standard” PD in that doping is disadvantageous to a more able athlete if the less able athlete is not doping (which would make this an alibi game).
SH shaped?
Iteration: Yes (although results of previous iterations are not very legible)
Reputation: Yes (again, legibility problems)
Enforceable contract: Yes – drugs testing and bans
Superrationality: No
The enforceable contract is probably the biggest effect here – just relying on iteration and reputation would be insufficient
SP shaped?
Because the solution is an enforceable contract the decision is not very SP shaped on an individual basis
Negotiating what the contract should be is SP shaped
What makes a medical exemption ok?
How much inhaler is an ok amount?
Cold war nuclear arms race
PD shaped
Making more nukes is equivalent to defect
SH shaped?
Iteration: Yes, treaty followed treaty. Inspections were allowed to verify adherence.
Reputation: A bit but probably not in a relevant way
Enforceable contract: Not really – if one country reneged then it’s not like the other country could sue
Superrationality: Yes. It seems both players realised D-D was terrible and wanted to play C-C. They couldn’t rely on just this so iteration was very important.
SP shaped?
Deciding the terms of the agreement is SP shaped
What size arsenal is better for which country?
Which particular weapons are better for which country?