O uporabnosti teorije iger

Aleš Praprotnik

Ariel Rubinstein, izraelski ekonomist in profesor na Hebrew University in New York University, je eden izmed pomembnih avtorjev na področju ekonomske teorije iger. Ta se posveča matematičnemu proučevanju procesov strateškega odločanja in interakcije ljudi (skupin ljudi) v različnih družbenih situacijah in položajih (igrah) na podlagi bodisi sodelovanja ali konflikta (zelo znana igra je npr. ‘ zapornikova dilema’). Kot taka ima mnogo skupnega s psihologijo in filozofijo in bi bila lahko precej uporabna pri konkretnih družbenopolitičnih odločitvah. Toda, ali je res?

Rubinstein v sicer starem intervjuju pravi (naj brž kontroverzno za mnoge teoretike iger), da ne in da je vsak nasvet običajnega laika enako uporaben kot bi bil nasvet na podlagi teorije iger:

Five: What are the applications of game theory for real life?

AR: That’s a central question: Is game theory useful in a concrete sense or not? Game theory is an area of economics that has enjoyed fantastic public relations. [John] Von Neumann [one of the founders of game theory] was not only a genius in mathematics, he was also a genius in public relations. The choice of the name “theory of games” was brilliant as a marketing device. … I believe that game theory is very interesting. I’ve spent a lot of my life thinking about it, but I don’t respect the claims that it has direct applications.

Game theorists are very good at abstracting some very complicated situations and putting some elements of the situations into a formal model. In general, my view about formal models is that a model is a fable. Game theory is about a collection of fables. Are fables useful or not? In some sense, you can say that they are useful, because good fables can give you some new insight into the world and allow you to think about a situation differently. But fables are not useful in the sense of giving you advice about what to do tomorrow, or how to reach an agreement between the West and Iran. The same is true about game theory. A main difference between game theory and literature is that game theory is written in formal, mathematical language. That has advantages and disadvantages. The advantages are that the formal language allows us to be more precise, it allows us to get rid of associations that are not relevant and it allows us to better examine some arguments. The disadvantage of formal language is the level of abstraction, which has two main downsides. First of all, it makes the theory very far away from one minus epsilon of the population. Even among the academic community, most people who claim to use game theory hardly understand it. Secondly, abstraction has the negative side that once you abstract things, you miss a lot of the information and most of the details, which in real life are very relevant.

In general, I would say there were too many claims made by game theoreticians about its relevance. Every book of game theory starts with “Game theory is very relevant to everything that you can imagine, and probably many things that you can’t imagine.” In my opinion that’s just a marketing device.

Five: Why do it then?

AR: First, because it is interesting. And I’m not saying it isn’t useful in indirect ways. I believe that intellectual thinking – philosophy or logic or game theory – is very useful in the cultural sense. It’s part of the culture, it’s a part of our perpetual attempt to understand ourselves better and understand the way that we think. What I’m opposing is the approach that says, in a practical situation, “OK, there are some very clever game theoreticians in the world, let’s ask them what to do.” I have not seen, in all my life, a single example where a game theorist could give advice, based on the theory, which was more useful than that of the layman.«

Ariel D. Procaccia, profesor računalništva na univerzi Carnegie Mellon, se do določene mere strinja in pravi:

»… many people are familiar with one of game theory’s most famous test cases: the Cold War. It is well-known that game theory informed U.S. nuclear strategy, and indeed, the interaction between the two opposing sides — NATO and the Warsaw Pact — can be modeled as the following game, which is a variation of the famous “Prisoner’s Dilemma.

So it would seem that game theory has saved the world from thermonuclear war. But does one really need to be a game theorist to come up with these insights? Game theory tells us, for example, that different forms of stable outcomes exist in a wide variety of “games” and computational game theory gives us tools to compute them. But the type of strategic reasoning underlying Cold War policy does not directly leverage deep mathematics — it is just common sense

Toda za razliko od Rubinsteina pripoznava, da teorija iger ima praktične aplikacije in lahko ponudi nasvete, pretežno v polju nadzorovanih elektronskih sistemov, kjer so pravila vnaprej določena, igralci pa dostikrat resnično racionalni, kot povečini predvideva teorija (npr. računalniki). Taka primera sta spletne igre (npr. poker) ali elektronske avkcije, pa tudi urejanje prometa. Procaccia:

»… game theory is useful for, well, playing games. Modern software agents that play games like poker (such as the ones from Tuomas Sandholm’s group at Carnegie Mellon University) do in fact use rather advanced game theory, augmented with clever equilibrium-computation algorithms. Game theory actually works better when the players are computer programs, because these are completely rational, unlike human players, who can be unpredictable.

Game theory is also useful for designing auctions. … The beautiful idea underlying the second-price auction has inspired similar insights that guide the design of sophisticated auctions for goods worth billions of dollars, such as rights to transmit over bands of the electromagnetic spectrum. And while this application of game theory seems fundamentally different from playing poker, the two are in fact similar: both involve interactions taking place in closed, controlled environments, where the rules of the game are specified exactly.«

Procaccia navaja tudi primer konkretne človeške situacijske aplikacije in sicer primer varovanja objekta in napadalcev:

»… especially exciting example comes from Milind Tambe’s group at the University of Southern California, a project I have collaborated on. Their work models security situations as a game between a defender (e.g., airport security) and an attacker (e.g., a terrorist organization or a smuggling ring).

Similar game-theoretic models have been around since the 1960s, but it is only in the last decade that researchers have begun to understand the computational aspects of these games. Tambe and his group have gone as far as implementing and deploying algorithms that prescribe a security policy by computing the defender’s optimal strategy. These algorithms are currently in use by the Los Angeles International Airport, the U.S. Coast Guard, and the Federal Air Marshal Service

Podobno aplikativnost navaja tudi Economist, a Procaccia zaključuje: »Game theory is typically not useful, but when it is, it shines

Meni osebno se postavlja vprašanje, ali ne bi enakih organizacijskih in dogovornih učinkov dosegli z razumevanjem človeške psihologije (predvsem strahu kot poganjalca človeških dejanj), razumevanjem sočloveka, boljšimi medsebojnimi odnosi in z večjim medsebojnim sodelovanjem? V vsakem primeru pa je polje teorije iger interesantno in zanimivo bo spremljati, kaj nam lahko še ponudi.

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