The Jolly Contrarian

Prisoner’s dilemma: Difference between revisions

Page Discussion

Prisoner’s dilemma (view source)

Revision as of 14:31, 15 March 2022

1,270 bytes removed ,  15 March 2022
no edit summary
No edit summary
No edit summary
 
(8 intermediate revisions by the same user not shown)
Line 1: Line 1:
{{a|glossary|}}{{a|risk|}}{{risk|Trust}}ing is a risky strategy. Generally one side doesn’t survive. How can {{risk|trust}} survive?
{{a|bi|{{prisonersdilemmatable}}}}The [[prisoner’s dilemma]] is the mathematician’s way of articulating the [[commercial imperative]].


An exercise in calculating economic outcomes by means of {{tag|metaphor}}, the [[prisoner’s dilemma]] was developed at the RAND corporation in the 1950s by those splendid brainboxes as a way of predicting individuals’ behaviour in situations requiring [[I believe|trust]] among strangers - for very good example, when unacquainted participants buy or sell in an unregulated market. This field developed into [[game theory]].
An exercise in calculating economic outcomes by means of {{tag|metaphor}}, the [[prisoner’s dilemma]] was developed at the RAND corporation in the 1950s by those splendid brainboxes as a way of predicting individuals’ behaviour in situations requiring [[I believe|trust]] among strangers - for very good example, when unacquainted participants buy or sell in an unregulated market. This field developed into [[game theory]].


===The original dilemma===
==The original prisoner’s dilemma==
Two people are  charged with a conspiracy<ref>Whether or not they are guilty is beside the point. If it helps you empathise with their predicament, assume they’re innocent</ref>.  Each is held separately. They cannot communicate. There  is enough evidence to convict both on a lesser charge, but not the main charge. Each prisoner is separately offered the same plea bargain. The offer is:
Two people are  charged with a conspiracy<ref>Whether or not they are guilty is beside the point. If it helps you empathise with their predicament, assume they’re innocent</ref>.  Each is held separately. They cannot communicate. There  is enough evidence to convict both on a lesser charge, but not the main charge. Each prisoner is separately offered the same plea bargain. The offer is:
*If A informs B but B refuses to inform on A:
*If A informs B but B refuses to inform on A:
Line 14: Line 14:
**A will get 1 year in prison  (on the lesser charge).
**A will get 1 year in prison  (on the lesser charge).
**B will get 1 year in prison (on the lesser charge).
**B will get 1 year in prison (on the lesser charge).
{{prisonersdilemmatable}}


===The [[eBayer’s dilemma]]===
Another way of looking at this, for those easily triggered, is as the [[eBayer’s dilemma]].
{{eBayer’s dilemma}}
The consequence is easier to see in more familiar context. This version {{author|Douglas Hofstadter}} once described as the "briefcase came", but Millennials will recognise it as the [[eBayer’s dilemma]].  


Strangers consider a settling a transaction they have drunkenly agreed on eBay to purchase a set of complete boxed set of the final season of ''Some Mothers Do ’Ave ’Em'' on VHS, for £100<ref>The eBayers don’t ''have'' to be drunk, but as we all know, most people on eBay ''are'', so this is a bit of dramatic colour.</ref>. The seller must pay and the buyer must post the videos simultaneously. Assume the seller would have sold the videos at any price over £50 (so the transaction represents a £50 profit for her), and privately, the buyer would have been prepared to pay £150 had that been the asking price (the transaction therefore representing a £50 profit for him).
===[[Single round prisoner’s dilemma]]===
 
When settling the transaction, each has the following risks:
*If the seller posts ''and'' the buyer pays:
**The seller will get £100 but will lose a video it values a £50 (+£50).
**the seller will get a video it values at £150 but must pay £100 (+50)
*If the seller posts, but the buyer does not pay:
**The buyer will have video it values at £150 for free (+£150)
**The seller has given away a video it values a £50 for nothing (-£50).
*If the buyer pays but the seller does not post:
**The buyer will have paid £100 for nothing (-£100)
**The seller will receive £150 and will still have the video it values a £50 (+£200).
*If the seller does not post ''and'' the buyer does not pay:
**The seller is in its original position (£0).
**The buyer is in its original position (£0).
 
===Single round prisoner’s dilemma===
If you play the game once, and in isolation — with someone you don’t know and whom you do not expect to meet again, the payoff is grim: those who cooperate will get ''reamed''. Cooperation is a bad strategy. Your best interest is in defecting on the other guy, because ''his'' best interest is defecting on ''you''.  
If you play the game once, and in isolation — with someone you don’t know and whom you do not expect to meet again, the payoff is grim: those who cooperate will get ''reamed''. Cooperation is a bad strategy. Your best interest is in defecting on the other guy, because ''his'' best interest is defecting on ''you''.  


Line 52: Line 33:
Now, as well as the short-term payoff, there is a longer-term payoff, and it ''dwarfs'' the short term payoff.  If I defect once, I earn £150. If I cooperate a thousand times, I earn £50,000. If I defect first time round, sure: I am £100 up, but at what cost: if my counterparty refuses to play with me again — and if she tells other players in the market — I will struggle to make much money. ''No one will trust me''.
Now, as well as the short-term payoff, there is a longer-term payoff, and it ''dwarfs'' the short term payoff.  If I defect once, I earn £150. If I cooperate a thousand times, I earn £50,000. If I defect first time round, sure: I am £100 up, but at what cost: if my counterparty refuses to play with me again — and if she tells other players in the market — I will struggle to make much money. ''No one will trust me''.


{{seealso}}  
===''One prisoner, or ''two''?===
In our view, one correctly places the apostrophe to designate a ''single'' prisoner having the dilemma — so [[prisoner’s dilemma]], not ''prisoners’'' dilemma — because both prisoners if taken together ''have'' no dilemma: it is only where they are acting individually that they have a problem ... ''with each other''.
{{sa}}  
*The [[tragedy of the commons]]
*[[Agency problem]]
*[[Agency problem]]
*[[I believe]]
*[[I believe]]
{{ref}}
{{ref}}
{{draft}}
{{draft}}
Retrieved from "https://jollycontrarian.com/index.php?title=Special:MobileDiff/32578...62406"