Game Theory Calls Cooperation Into Question • Hacker News Board

Re: Game Theory Calls Cooperation Into Question

#31

Post by facepalm » Fri, Feb 13, 2015, 9:12 AM UTC

hyperion2010 wrote: post #2

Rather amusing title since it could be reworded as "Game theory still fails to explain biology." We know organisms cooperate. The fact that we consistently fail to find reasons to cooperate in game theory suggests that the simplifying assumptions that it makes are incorrect. To give only one example, what happens when agents can choose from among a set of games to play with opponents with known histories?

Organisms don't cooperate all the time, cheating is also common in the world of biology.

I find it fascinating that twisting the parameters changes the outcome. Thinking about our social world, for example fraud in finance, perhaps there is something to be learned about the way the rules of society should be set up to eliminate cheating.

Re: Game Theory Calls Cooperation Into Question

#32

Post by raverbashing » Fri, Feb 13, 2015, 10:05 AM UTC

klochner wrote: post #28

Many people seem to have game theory backward. Game theory is a modeling tool that assumes all relevant utility is baked into the payoff matrix. Games (payoff matrices) that capture unique outcomes/behaviors are often given memorable names from human situations that approximate the games. For example the matrix referred to as 'prisoners dilemma' demonstrates a situation where dominant actions give a suboptimal outcom…

> Game theory is a modeling tool that assumes all relevant utility is baked into the payoff matrix.

Correct, and they mostly use the prisioner's dilemma, which is very simplistic, and probably not what it happens in nature (or common situations) most of the time.

Re: Game Theory Calls Cooperation Into Question

#33

Post by ajuc » Fri, Feb 13, 2015, 10:24 AM UTC

kriro wrote: post #29

drawkbox wrote: post #16

Earlier quoted context omitted.

People do cooperate on a self-survival instinct though, cooperating now let's you get ahead of others together. However, there are always competition and hierarchies within the team/group as well that determine choices and game theory within the group cooperating. The larger the team or less dependent then the more each player may be unhappy or not doing the best for themselves personally. For the most part, people c…

For me comparative advantage (economics) was always enough to "justify" cooperation as a good general attitude in life.

Comparative advantage theory (like most of economy) is a misleading simplification.

Historicaly the countries that were on the "low profit" end of international trade and followed the comparative advantage theory advice - lost (see Argentina), and the countries that contrary to the theory tried to move to more complex products/services and bigger profits - won (see Germany, USA), even if they had to abandon their comparative advantages, suffer international trade restrictions, etc to get there.

It turns out industrialization not only makes you better at producing machines - it also makes you better at producing food, and almost everything else. Meanwhile producing food just produces food.

Re: Game Theory Calls Cooperation Into Question

#34

Post by mslot » Fri, Feb 13, 2015, 10:25 AM UTC

Evolution happens primarily in spurts with high selection pressure in which cooperation probably makes less sense than in stable populations with relatively low selection pressure.

Re: Game Theory Calls Cooperation Into Question

#35

Post by mcherm » Fri, Feb 13, 2015, 10:40 AM UTC

forkandwait wrote: post #5

Perhaps "cooperation brings game theory into question" would be a better title?

What is in question is not game theory (math really does aspire to "absolute truth") but whether this game theoretical model applies to typical biological populations.

Re: Game Theory Calls Cooperation Into Question

#36

Post by DennisP » Fri, Feb 13, 2015, 3:11 PM UTC

hyperion2010 wrote: post #2

Rather amusing title since it could be reworded as "Game theory still fails to explain biology." We know organisms cooperate. The fact that we consistently fail to find reasons to cooperate in game theory suggests that the simplifying assumptions that it makes are incorrect. To give only one example, what happens when agents can choose from among a set of games to play with opponents with known histories?

More like "one very simple model within game theory fails to explain everything in biology." There's nothing here that invalidates the whole of game theory. If the payoff matrix doesn't match reality, then the theory will make inaccurate predictions. Some models do predict cooperation (like the snowdrift game mentioned in the article). It just depends on what the incentives are.

Also worth mentioning that while the classic game theory approach is to calculate the optimum strategy, there's also evolutionary game theory, which looks at what strategies could actually be found by an evolutionary process. They tend to be the same, but not always.

"Choosing among a set of games" seems to me to be just a bigger game. "Known histories" can include any iterated game, which is a basic part of game theory. It's also studied a lot in the context of poker, where the challenge is that if you deviate from the game-theory optimal strategy to better exploit your opponent, you open yourself up to exploitation.

Re: Game Theory Calls Cooperation Into Question

#37

Post by elektronjunge » Fri, Feb 13, 2015, 3:19 PM UTC

KingMob wrote: post #9

hyperion2010 wrote: post #2

Rather amusing title since it could be reworded as "Game theory still fails to explain biology." We know organisms cooperate. The fact that we consistently fail to find reasons to cooperate in game theory suggests that the simplifying assumptions that it makes are incorrect. To give only one example, what happens when agents can choose from among a set of games to play with opponents with known histories?

Exactly correct. Why play with cheaters? The fundamental flaw in applying game theory to biology is to constrain the possible outcomes when unfairness is detected. In game theory, all you can do is change your strategy for the next round; in reality, we have multiple punishments to bring to bear, such as refusing to play, public shaming, fines, imprisonment, killing, etc. Game theory is only an "ok" model of cooperat…

That's not a problem with game theory. That's a problem with using overly simplistic games. You can easily model all of those punishments with different payouts in a game. In fact, when I studied it in school most of the games we worked through included punishment mechanisms.

Re: Game Theory Calls Cooperation Into Question

#38

Post by DennisP » Fri, Feb 13, 2015, 3:25 PM UTC

D_Alex wrote: post #3

> In a single instance of the prisoner’s dilemma, the best strategy is to defect — squeal on your partner and you’ll get less time. No, that is not right, if it was there would be no dilemma, and this subject would not be discussed ad nauseam. The whole point is that the situation is symmetrical for both players, they should reach the same conclusion and act the same way ... and using the strategy of cooperation thei…

Yes but the dilemma is that no matter what the other person does, you are better off by defecting. You get a good outcome if you both cooperate. If he defects, you get a horrible outcome if you cooperate. If he cooperates, you get a decent outcome by cooperating, but an even better outcome by defecting.

Since both players think this way, they both defect and get a bad outcome.

Real prisoners don't always defect, but the reason is that they're not actually playing the prisoner's dilemma. The payoff matrix has been altered....eg., by severe penalties for ratting, which give the player a much worse outcome for defecting. Those penalties wouldn't be necessary if the dilemma weren't real. (Another alteration would be if the prisoners care enough about each other so each sees it as a bad outcome if the other suffers. This isn't contrary to game theory, it's just a different set of payoffs.)

Re: Game Theory Calls Cooperation Into Question

#39

Post by elektronjunge » Fri, Feb 13, 2015, 3:28 PM UTC

nosuchthing wrote: post #12

Pack animals like dogs naturally discourage fighting amongst themselves [1]. Strife weakens the pack. Consider the effort it takes 1 person to build a house, or the amount of effort it would take to build an mp3 player alone from scratch. Game theory would have you believe the optimal way to win at poker is to booby trap the card table and rob your competition. [1] https://www.youtube.com/watch?v=hstLdzCg6l8

Correct and there are games that model that behavior, for instance iterated stag hunt[1]. This shows the benefits of cooperation for pack animals much more than the classic prisoner's dilemma. Of course you could construct a more detailed game that includes factors like defense and having a single leader that would be even closer to reality. The math behind game theory is right, its a question of whether we have chosen the right game to play.

[1] http://en.wikipedia.org/wiki/Stag_hunt