Prisoners' dilemma and Nash equilibrium | Microeconomics | Khan Academy

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Microeconomics on Khan Academy: Topics covered in a traditional college level introductory microeconomics course
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[@hafizullahamin7671]

Evolution of a Mathematicians career : Undergraduate => Graduate => Assistant Professor => Associate Professor => Professor => Prison Warden

[@Hades1980s]

I want to see my lawyer first.

[@frankfoo1223]

For some reason, i can never sit through the lecture of my professors, i'd either fall asleep or get bored with their analogy and start tapping on my phone but surprisingly I would sit through your videos and just keep replaying it if i dont understand it. Anybody else going through the same thing i am ? I also would come to your videos before going to any of my professors just because you are much more easier to understand.

[@69erthx1138]

You could drop $150k on an education that you could get on KZbin, then buy a sheep skin and transcript off the darkweb.

[@matik0701]

I'm sure if your professor would have a smartboard, a nice voice, and an easy example you would go to his lectures. We, like people, have changed over the past 20 years or so. Since multimedia became mainstream we changed our attention span and our expectations for entertainment. There have been numerous studies on our attention span. One showed that, because of cell phones (social media scrolling), our attention span has significantly decreased, which means we 'can' only comprehend something for a short time before getting bored and 'scrolling away'. Another thing is, we get bored by plain text, plain speech, etc. One of many studies showed that the same post (same text, same information) gets less attention (fewer likes and comments) on Facebook if it's only in plain text instead of a text and picture (without taking into account how related the picture is). I see asynchronous learning (videos) as the future of learning because you have a multimedia format (speech + pictures, graphics, videos) with enriches the experience (most of us are visual types, hence it helps us to understand something when it's already visualized) and helps remembering stuff (there's been a psychology experiment I think in the '80s where they tested short-term memorization of words by just reading them and a technique that uses non-related visuals, i.e. for each word you look at an object in your surrounding), and you also have the options to replay the video or pause it as you like, in that way dictating your own learning tempo.

[@keno1069]

@@matik0701 That experiment in the '80s reminds me of learning a new language using Rosetta Stone. They say the word and show the picture. Brilliant!

[@zacharycat]

This is one reason people sometimes confess to crimes even when they are innocent.

[@NibsNiven]

"This is one reason *fools* sometimes confess to crimes even when they are innocent." FTFY.

[@akshatgupta8523]

With the american judicial system of juries giving out a verdict, can't say if they are actually fools.

[@alejandrocanas6744]

@@akshatgupta8523 exactly, well said.

[@hashvid]

In some countries admitting a traffic offence is cheaper and time saving than fighting/ reasoning it. Wonder if it falls here

[@idon.t2156]

"Capturing the Friedmans"

[@RotMGMill]

I am honestly fascinated by that perfectly written 'g' in the word 'drug'

[@theMosen]

I'm more fascinated by the invisible 'l' and 'i' in "Equilibrium".

[@bustinbinden]

It's a nice g Hows the last 6 years been?

[@Thulgon]

Nice try, FBI, but I'm still not confessing.

[@69erthx1138]

That's funny. Game theory for the cromagnon jock.

[@alexeilindes7507]

Plead tge fith upon intro

[@fitonation]

Lmao 🤣🤣🤣

[@DonRua]

We spent one class on this ... some 36 years ago. I have always been fascinated by this but never found the time to read further. A few years back that prof even passed away. Now staying home, I will learn this. Thank you Wuhan lol

[@elenichristaki2465]

I'm really impressed. It's a truly interesting theory. I have seen the "A beautiful mind" and i was stunned by this incredible man (Nash). I appreciate video's creator helping me understand Nash Equilibrium.

[@NoraGreen1992]

Thank you so much omg. You saved me. Game theory is driving me nuts.

[@iAnon666]

thank you so much, the global equilibrium vs nash equilibrium helped SOO much. idk why anyone would EVER leave out the global equilibrium concept when explaining this. especially when nash equilibriums take into account unilateral incentive. THANK YOU!

[@oliverarmitage1966]

Man this guy has been helping me from Y1 of my comp sci course right to the very end

[@allielee]

I'm Al and I'm denying, hopefully Bill will do the same

[@kimyongun5471]

well, I'm Bill and I have one bad news for you

[@user-gt3us4lp6e]

@@kimyongun5471 o your kim

[@Maxwell_Maher]

Bill Deny the Prisoner Guy

[@weicong1533]

HAHAHAHAHA

[@andres6868]

RIP John Forbes Nash

[@cherrykim5989]

Thank you so so much for making such a wonderful explanation of this because my lightbulb in my head went 'DING' instantly after- I HAD SO MUCH TROUBLE UNDERSTANDING THIS WHOLE CONCEPT before- YOU ARE THE BEST!!

[@jaminjewel135]

The explaining is wonderful and is easy to understand

[@cristianoronaldo9ism]

I'm baffled by the fact that Sal hasn't won the Nobel Prize yet.

[@NibsNiven]

You are easily baffled.

[@mohammadomar6680]

he has not, but the person who invented this method, John Nash, won the nobel prize :)

[@shosecor4986]

@@mohammadomar6680 thank you for explaining this, man, I was baffled too

[@parthprashar8498]

@@NibsNiven Lmao. Give him a break dude he must have been cursed with bad professors and sources.

[@sadeekmuhammadryan4894]

One of the best videos on youtube. The explanation was very nice and clear. ❤️

[@Arafat-my6fe]

After having failed to get my head around this theory watching on Crash couse and Scihow, Sal came to my mind and it just paid off as always. Sal is a true gem.

[@Mayacocoice]

Im in love with your voice haha, you helped me so much during my bio exames

[@nietzschesghost8529]

3 years in prison with a reputation as a snitch is greater than 10 years in prison as somebody who got snitched on.

[@v.m.9198]

Thank you for doing this. Hopefully I'll pass my midterm now

[@jeromejoseph6897]

Thank you for explaining this. I loved it.

[@aghamusaseyidaliyev5564]

Perfect clarification Thank you very much

[@dchangebegins]

Salman khan..u make study so fun. I have seen so many of ur video I can make out ur voice evn wen sleeping. Why don't clg prof teach like you. Or just come n play your video in class that will be enough. Great job carry on u r d real star.

[@rinchendorji9112]

This is so relevant even after a decade....thank u

[@lelenmate9741]

Both deny is the state of " Pareto Optimality".

[@EmotionalContagion]

@khanacademy your videos are excellent - all of them!! Tx for your efforts. they are greatly appreciated!

[@TheZombaslaya]

being a good DA is being a good hustler.

[@VersusARCH]

Funny thing no prisoner considered a possibility that the offer was a lie...

[@PupeNaty]

Very good explanation!

[@Dummychan6677]

You explain really well !

[@lashau7056]

Now education is truly free thanks to Khan Academy

[@zaidradwan4000]

Thank you for the useful information

[@SC00PPHASE]

Darn that spelling mistake. "Equibrium."

[@neilsokayatthis3970]

Finally it clicked 🙏 khan academy never disappoints

[@MrLogiu]

Thank you!

[@brendenmattkost]

The confession/confession scenario is very very very stable

[@monatahan635]

can you fast forward the time it takes ou o type or type beforehand?

[@Gnurklesquimp]

Are there any universal techniques to detect these in games? I guess they will be quite obvious alot of the times, even moreso when you're good at the game, but it's hard to be good at a game still in developement.. I'm going to say the answer is probably no, and that I just need to get together some minds and do a huge load of testing.. And if they're problematic in the sense that they reduce the amount of viable decisions into a linear period of decision making, fixing them would perhaps be even harder..

[@alauc]

I have introduced several thousands students to this theory and through social action prepared them for real life. As you can imagine in short run dishonest win, in long run honest ones. In fact 85% explain moral capital and firms and countries who play fair are winners. So God does control output, money is pure reflection of moral, intellectual, and social economy.

[@efhh7569]

11th you 22nd, so 2nd 1 11th 11aw3 the 26th sq2q12 Q10 w32

[@greatthinker3444]

nice work lecturer

[@nandha0150]

thanks a lot for the wonderful explanation sir. Love from India :)

[@ShivneilTV]

It looks so easy when you explain it, but when I try to do it on my own, my mind goes blank haha

[@paul1964uk]

This is off topic but I wonder if queuing (standing in line), where the serving time is proportional to (say) numbers of checkout items, could be treated by economic analysis in some way. While "first come first served" is fair (and upholds trust etc) there is the collective waiting time of for the people behind first place. People can switch in pairs, you see. So how could the line move to towards an 'optimal' arrangement under this type of approach?

[@MellyXNY]

great video

[@ghirardellichocolate201]

While win win situation is not for everyone, we shall check further on John Nash and what is he trying to equilibrate.

[@rafatyusufi6711]

good topics

[@NatsFan18]

Good explanation. Only thing I'd say is that the risk of not confessing in this case is so much greater (8 more years in prison) and reward of not confessing (just 1 year less in prison) make it a no brainer to confess. If the reward for both not confessing was greater (say 5 less years of prison) then it would be more tempting to take the risk and not confess. But the point of the video is to explain how the game theory works...which he successfully does

[@NibsNiven]

"a no brainer to confess" Nonsense. It is always better not to confess.

[@BenjaminShadey]

What about the added idea that the guy serving 1 year will probably get shanked and die for dropping a dime on his buddy?

[@varunrajesh6516]

Benjamin Shade They're not buddies though. They've never met each other.

[@wave0507wave]

Benjamin Shade maybe they wore a mask while robbing the place

[@69erthx1138]

Sal does state outside interest is elimanated....nonlinear terms must be added in a subtle way. 😁

[@yo-rh8lk]

Its a shank or get shanked world out there. Shank the shanker to not get shanked. Dont shank the shanker, get shanked. Before yk it there will be piles of shanked bodies.

[@PyroK8]

That's why we should make a universal rule. "DON'T SNITCH." There is never a reason to snitch. Snitches get stitches or end up in ditches.

[@NibsNiven]

They also frequently get screwed by the prosecutor. BTW there is almost always a reason to "snitch". Crooks get away with crime because of spineless people. I "snitch" on people all the time and always will, because I care about more than myself.

[@tygeros2955]

this is why I snitch

[@bestbotreview]

Khan vict music... You Kahn do it!!! im here for that prisoner dilemma 23 32 10101 aint nothing but a G thing

[@LuisFernando-yd3mx]

As they say in the streets, snitches get stitches, and homies don't rat out homies. Prisoner's Dilemma doesn't work when there is loyalty amongst the thieves.

[@jorgequiroz881]

excelent video

[@dheerajhazarika1836]

Fantastic

[@chukwumau.5696]

finally understood. thanks khan, keep it up.

[@amanpratapsingh1243]

Hie man ssup!

[@hisenburghkizarwilhelm4570]

@@amanpratapsingh1243 he is dead...its been 8 years

[@kundankumar-fi3zj]

❤ thankyou sir

[@adityatiwari604]

the fact that sal addresses both the culprits who were caught red handed selling drugs as gentlemen is just hilarious!

[@DanielBrownsan]

There's no need to repeat things as you write them. There's no need... to repeat things.... as you write them...

[@EloisaLira]

Thanks, great explanation

[@meghand8682]

*explanation

[@EloisaLira]

Meghan D thanks, I'm learning English

[@mohsinsmir3104]

If they both confess ...it means they have a dominant strategy...

[@irmb5teS]

omg this reminds me of a beautiful mind ;)

[@TosinDFreshPrince]

i learnt this first in a manga, liar game, wanted to know more about it

[@sudarshanduvvuru2810]

mashallah badiya video inshallah lover me this vidheo

[@cleanseroftheworld]

But hey, that's just a theory... A Game Theory. Thanks for watching.

[@chuckthrows]

cleanseroftheworld hahaha

[@user-pt2ln7fe3e]

Thats why Going alone is the best.

[@paolocogliati4084]

Does this break down if for example the equilibrium state is 6 years instead of 3?

[@hermanthegerman9874]

Dear Sir Kahn, I worship you, I really do, and I never thought I‘d see you giving a flawed explanation but today is the day. :-( The way you explain it, it‘s mixing up the concept of „dominant strategies“ and „Nash equilibria“, which might be very confusing to students. In this special case of the prisoners dilemma, the state „confess/confess“ is both: an overlapping of the two dominant strategies „confess“ AND a Nash equilibrium (because the overlap of dominant strategies is ALWAYS also a Nash equilibrium), BUT a Nash equilibrium can perfectly exist without dominant strategies being around. They way you explain and derive it in the beginning, it seems that „confess/confess“ is a Nash equilibrium because it’s the overlap of the two dominant strategies „confess“, but the real reason why „confess/confess“ is a Nash equilibrium, the very core concept of the Nash equilibrium, is only what you start to explain at around 7:50. So to every student who reads this: Don’t confuse these two concepts! Greetings from a former RWTH Aachen Tutor.

[@torchinaces]

what program does he draw on? or use?

[@marsch000]

Al and Bill are like brothers

[@avieus]

Another way to frame it ( per player) best & worse scenarios when confessing is 1 and 3 years, respectively. best & worse case scenarios when denying is 2 and 10 years, respectively.

[@Larry21924]

Your insights are extraordinary; just like a book that was deep in its exploration. "Game Theory and the Pursuit of Algorithmic Fairness" by Jack Frostwell

[@meanmanturbo]

Cool, game theory

[@Zenovarse]

People dislike school but likes KZbin. How fascinating.

[@charleanc.nobleza7969]

Hi Em

[@fauxpas4589]

Awesome dilemma but confessing to an armed robbery that doesn't exactly look too good once you're out. Well, neither does doing 10 years for drug charges lol

[@jiibbi5584]

thought this is a bit familiar and realized how watching Running Man for all those years helps me understand this more quickly. lol their loyalty test episodes are somehow like this 🤣

[@YouNotACopJRied]

So Henry pretty much used this scenario in snitching and confessing in GoodFellas?

[@stankwho]

Is there an echo in here?

[@hollyireton2526]

i searched long and hard for this comment

[@NibsNiven]

Why do you frequently repeat your words right after saying them?

[@ethanchow4929]

your a legend

[@bhanupratap4595]

chup chutiye :D

[@milfordjohnson2289]

ive either thought about this equilibrium too much... or i was accidentally thrown into a parallel universe where everyone and everything part takes in a weird, oddly saddistic thought experiment with no end 😬 i suppose it is possible that the nash equilibrium itself, as a topic, causes symptoms of the disease suffered by dr nash himself.

[@sagarnandi6276]

"A beautiful mind" brought me here

[@jas-hy3sy]

Somewhere in the world, before making their decisions... Bill and Al are watching this Khan Academy video.

[@ClambNStuff]

Well, what about the state classification of “snitch” where it doesn’t matter how many years you’ll be in prison because you’ll be dead. Interesting concept though

[@TheYoungExec]

😂😂☝️

[@ClambNStuff]

I think I worded this wrong, but I’m just saying that the factor of snitching and repercussions aren’t included.

[@EvanEvansE3]

It's about risk. Ratting out the other guy limits your risk from 5x to just 1.5x. It's a very good tradeoff given the potential risk.

[@dms807907]

He got it wrong... if you confess you don't get one year in prison you get one year to live

[@murligscorpio]

Pls share what if there are more parties how this concepts works.

[@shadowunifer]

Take a look at the Oligopolies, Duopolies, Collusion, and Cartels video.

[@bibekhood]

Both individuals, acting as rational decision-makers, opt for the less risky choice of confessing, given that the risk associated with denial is greater for both of them. In other words, they both select the three-year option due to its lower risk.

[@monatahan635]

how does this affect businesses?

[@llr097]

wow.

[@MrVpassenheim]

I understand this in the way of explaining Nash equilibrium, but from a law enforcement perspective how does choosing the "optimal" outcome from the prisoners' perspective (both confess) accomplish justice if the prosecutor was, in fact, wrong about his assumption in the first place about the other crime in question? He would have just gotten 2 men to confess to another crime they weren't guilty of and the real criminals get off scot-free. I guess it's proving that the Nash equilibrium actually pans out further than calculated? It certainly isn't good law enforcement, in fact, in many ways they've actually made things worse - justice was perverted in the case of 4 people (2 got away with it completely, 1 got a reduced sentence for lying, and 1 got an increased sentence for telling the truth!). I think it would be good to present a caveat to this illustration in advance!

[@jonathonbryan]

love this dilemma, and beautifully explained. but if i was the guy trying to get them to confess i wouldn't give this test, since what if they didn't do the crime? by this logic, maybe they'd still both confess! so if they actually did commit the crime, and they both confess to it, i still wouldn't know if they had done it or not!

[@jean94zoo]

Yes but officials don’t care about the truth, they still getting paid anyway, they juste need a guilty person

[@motogrey3707]

Senario V: Al confesses gets one year; Bill denies, beats the charge; gets two years. Al doesn't live out the year.

[@Fl0pus]

hello people from ECO100, good luck with exams tomorrow :D

[@erickjuma7643]

Most Bills I know won't even listen to the FBI guy giving him such crazy options

[@eggizgud]

I don't understand the fourth possibility. Why should both confessing mean a stiffer punishment than the original?

[@thebigmonster2010]

Nash Equibrium

[@buugey9494]

Al got red handed selling drugs, hahahaha

[@eliotwolfert8488]

This is in reference to oligopoly collusion right?