Games real people play

Games Real People Play

Gotcha! You thought this was going to tell you where to find computer games on the web. Instead, it’s about game theory. As penance for my sins, try this game and then return here.

That was the Prisoners’ Dilemma. Where’d the name come from?

Imagine that you and an accomplice (someone you have no feelings for one way or the other) committed a crime, and now you’ve both been apprehended and thrown in jail, and are fearfully awaiting trials. You are being held in separate cells with no way to communicate. The prosecutor offers each of you the following deal (and informs you both that the identical deal is being offered to each of you – and that you both know that as well!) “We have a lot of circumstantial evidence on you both. So if you both claim innocence, we will convict you anyway and you’ll both get two years in jail. But if you will help us out by admitting your guilt and making it easier for us to convict your accomplice – oh, pardon me, your alleged accomplice – why, then, we’ll let you out free. And don’t worry about revenge – your accomplice will be in for five years! How about it?” Warily you ask, “But what if we both say we’re guilty?” “Ah, well, my friend – I’m afraid you’ll both get four-year sentences, then.”

Now you’re in a pickle! Clearly, you don’t want to claim innocence if your partner has sung, for then you’re in for five long years. Better you should both have sung – then you’ll only get four. On the other hand, if your partner claims innocence, then the best possible thing for you to do is sing, since then you’re out scot-free! So, at first sight, it seems obvious what you should do: Sing! But what is obvious to you is equally obvious to your opposite number, so now it looks like you both ought to sing, which means – Sing Sing for four years! (Douglas Hofstadter, Metamagical Themas, p. 716)

But that’s just a story to explain the name. What’s interesting is the structure – people trying to do the best they can dealing with others who are also trying to do the best they can. Sometimes – as the prisoners found out – it can look like everybody doing the best they can makes everyone worse off.

As soon as I say something like that, though, I rebel: It can’t be that I shouldn’t do the best I can – can it? And, even if I did, what about all those other people who wouldn’t stop doing the best they can? Isn’t not doing my best just a prescription for taking the rap while the other guy goes free?

That kind of situation – not just the Prisoners’ Dilemma, but beings who are doing their best when what the best is depends on what others are doing – is at the heart of game theory. And game theory is at the heart of half a dozen disciplines, from economics to international relations to evolutionary biology to sociology to ....

Anyhow – enough prologue. Here are some links:

Al Roth’s Game Theory and Experimental Economics Page

More to come!