Applied Complex Systems

a Prisoner's Dilemma. (c) Fox Broadcasting, image courtesy stripedwall.com

a Prisoner's Dilemma. (c) Fox Broadcasting, image courtesy stripedwall.com

I took a political science class in college taught by Scott Page, a professor in complex systems, and while I unfortunately slept through many of the lectures it was still one of my favorite classes. Three points from that class stuck with me in particular, and I want to mention and discuss them here.

The first is probably Professor Page’s most famous contribution. It relates to the value of diversity, and it seems to be one of those ridiculous quirks of fortune that he produced it at Michigan right after the huge Supreme Court cases on diversity. It turns out that diversity isn’t just a guilty white liberal platitude, but is instead really the best way to maximize the effectiveness of a group under very general conditions. There’s a very good summary of the work here that makes the idea accessible without skimping on the subtleties of the actual science. You can use the lesson here to bring some quantitative support to theories about management (i.e., schools or businesses should indeed aim to maximize diversity in their members) or about personal development (i.e. you’re never gonna hone that intellect if you don’t expose yourself to some differing perspectives), or probably other parts of life as well.

The second relates to game theory, which I was thinking about last week with respect to Internet privacy (this stuff comes up all the time in the real world!). The classic problem in game theory is the prisoner’s dilemma, which was recently dramatized in a simplified form with the prisoners on ferryboats in The Dark Knight.The trick to the prisoner’s dilemma is that, no matter what the other boat does (i.e., blow your boat up or not), things will always go better for you if you to choose to sink them, so the rational thing to do is to blow the other side up. But of course the best possible outcome only occurs if both sides act irrationally and cooperate.

To understand this puzzle, researchers formulated the iterated prisoner’s dilemma, where two players face off repeatedly, and can therefore punish each other in future encounters for bad behavior in the past. The iterated prisoner’s dilemma is basically the simplest possible model of interpersonal relationships, and yet it has taken decades of research to start understanding its implications. One goal is to find guidelines for players to follow to get the best long-term outcomes against any type of interlocutor, and it turns out the best solution here is extraordinarily simple. It’s known as “tit for tat”, and all it says is that you should start by cooperating with the other player (i.e., assuming good faith), and in each subsequent game treat the other player like he or she treated you in the last game.

(c) Warner Pictures, image courtesy screenmusings.org

(c) Warner Pictures, image courtesy screenmusings.org

There’s so much more to say about the prisoner’s dilemma and the tit for tat rules (and there’s plenty written out there if you’re curious, or you can discuss in this very thread!) but the first lesson for me is that, just as the prisoner’s dilemma comes up in all sorts of situations in real life, tit for tat is also a very good set of rules to follow in real life: in dealing with other people, always treat kindness with kindness, never tolerate cruelty from others, and always start with kindness and the assumption of good faith.

The third point is Arrow’s Theorem, but this post is already getting long, so I’ll save that for another time.

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2 Responses

  1. I forgot if we talked about this, but I think you would like Tom Slee’s “No One Makes You Shop At Wal-Mart” — it uses the prisoner’s dilemma to show why conservative “marketthink” ideology doesn’t hold up.

  2. Thanks for the link! It struck me as I was thinking about your comment that classical economics and game theory share pretty much the same assumptions as far as I can tell (people make individual rational choices to maximize their utility). So I just read chapter 1 from that book (in case anyone else is curious, it’s available at the author’s website, and scroll down to “Jack Shops at Wal-Mart” for thee introductory example). And you’re right, I really do like his point! I’ll try to say more on it soon

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