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'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

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Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#51

Post by Practicality »

Danihan wrote: post #45
majewsky wrote: post #40

Earlier quoted context omitted.

A good reputation score would start out at +/- 0 and not punish you for being the lone righteous guy in an otherwise immoral neighborhood.

It does, no one really has a net worth one way or another when they are a child. Define righteous? Define immoral? Capitalism rewards providing actual value to people. It doesn't reward shallow niceties and self-righteousness, those are common.

Capitalism sometimes rewards those who provide value, but more often than not has no problem rewarding people for spouting self-righteousness.

If you think that everyone who gets rewarded in a capitalist society do so because they provide value then you have to ask: What value do scam artists provide?

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#52

Post by morogop »

jdonaldson wrote: post #46

As mentioned elsewhere in this thread, the payoff for these games never takes into consideration reputation effects. That is, what's the result of other participants observing your actions? Are they more likely to trust you or not trust you when you interact? I mention this because it's clear that we're changing the way we trust and interact with each other online. Whether it's virtue signaling or trolling, we're ado…

All actual study of these games involves both one-time and repeated versions of the games, which changes those dynamics.

Reputational effects are interesting. If you wanted a reputation as an intelligent person, you'd learn something before you post. But you realized that HN rewards snarkiness and superiority, not actual intelligence, so you're posting ignorantly, and pretending you're making some wise point. Your post will get upvoted because of your decision to embrace ignorant arrogance.

Mine, on the other hand, will be downvoted, because I was very slightly mean to you, and HN doesn't tolerate rudeness toward white men who think they're smarter than they are. After all, that's HN's core demographic.

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#53

Post by pbhjpbhj »

jerf wrote: post #31
TheSpiceIsLife wrote: post #4

These experiments are nonsense. Firstly, from the article: “In principle, natural selection predicts individuals to behave selfishly” is a faulty premise. Obviously humans who cooperate to raise children to sexual maturity will have more descendants. Secondly, in these simulated games it seems likely to me the participants would be, at least to some extent, randomly selecting cooperate / defect because a potential mo…

"while our worldview is "everything is a competition" that is how we will interpret what we see." If you think that the idea that competition is rife is merely a product of our world view, stop competing for a while and see what happens. You may have to think carefully about what all constitutes "competition"; you come from a very long line of survivors and there's a lot of competitive behaviors that come naturally t…

Scarce resources can be coped with by both cooperation and competition (and other modes?). If there's limited water, we can share it - thus enabling us to have more people to hunt/gather resources. If you keep all the water you'll be stronger, but perhaps you'll hunt less effectively, struggle to gather enough resources, etc..

Competition isn't always the best way to cope with limited resources.

Competition between different groups within which there is cooperation, that's another option, of course.

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#54

Post by whack »

TLDR: In Prisoner's Dilemma, defecting is a dominant strategy, and both players defecting is the only Nash equilibrium. In Snowdrift, there is no single dominant strategy, and no Nash Equilibrium exists at all.

By design, the Snowdrift game rewards cooperation more than Prisoner's Dilemma, so it's no surprise that people cooperate more in Snowdrift. The real question is which game better models reality.

http://www.gametheory.net/dictionary/DominantStrategy.html

https://en.wikipedia.org/wiki/Nash_equilibrium

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#55

Post by jzl »

I've seen a couple of oblique references to this in other comments, but I'll go a little deeper: if you want to truly understand the prisoner's dilemma scenario and how it relates to human, or more generally, animal behavior, there is incredible coverage of the topic in Richard Dawkins' The Selfish Gene. He pioneered the idea of running PD "competitions" in an attempt to discover the best evolutionary strategy for PD, and how these strategies might predict large-scale behavior in animal populations. Each competitor (other scientists and researchers) submitted a strategy for handling the PD in the form of written code that could face off against other strategies. Each round of competition consisted of thousands of iterations of the game. Some strategies were simple and some were incredibly complex. Across two competitions, the second with 60 competing strategies, the simple and "non-cynical" strategy called tit-for-tat won handily. (Tit-for-tat is mentioned briefly in the original article without any explanation.) This is the strategy:

- Unless provoked, the agent will always cooperate.

- If provoked, the agent will retaliate.

- The agent is quick to forgive.

- The agent must have a good chance of competing against the opponent more than once.

The fact that this strategy was a consistent winner in his competitions has led Dawkins to argue that "nice guys finish first" and could be a partial explanation for certain forms of so-called "altruistic" animal behavior -- behavior that seemingly gives no benefit to the altruist, except for the fact that too may benefit when it is their turn to be helped. See also:

https://en.wikipedia.org/wiki/Nice_Guys_Finish_First

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#56

Post by jzl »

jdonaldson wrote: post #46

As mentioned elsewhere in this thread, the payoff for these games never takes into consideration reputation effects. That is, what's the result of other participants observing your actions? Are they more likely to trust you or not trust you when you interact? I mention this because it's clear that we're changing the way we trust and interact with each other online. Whether it's virtue signaling or trolling, we're ado…

See my other comment. In the competitions discussed in The Selfish Gene, PD strategies are allowed to have memory and the simulation is run thousands of times per round. However it is pretty consistently the case that long-term memory is not an outright win for either the competitor or the opponent, compared to the simple "tit-for-tat" strategy which only remembers the previous iteration.

Of course the PD only models certain kinds of human/animal interactions. Knowing that a particular person is a cheater or is vindictive or whatever is obviously important for evolutionary strategy as a whole. But the question is more about heterogenous populations. Is there an optimal strategy that wins more than any other across a wide range of opposing strategies, including if everyone else is actually using the same strategy?

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#57

Post by cgmg »

whack wrote: post #54

TLDR: In Prisoner's Dilemma, defecting is a dominant strategy, and both players defecting is the only Nash equilibrium. In Snowdrift, there is no single dominant strategy, and no Nash Equilibrium exists at all. By design, the Snowdrift game rewards cooperation more than Prisoner's Dilemma, so it's no surprise that people cooperate more in Snowdrift. The real question is which game better models reality. http://www.ga…

"In Snowdrift... no Nash Equilibrium exists at all."

Doesn't that contradict Nash's existence theorem? I believe Snowdrift has 2 (pure) Nash equilibria, namely CD and DC.

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#58

Post by baddox »

nostrademons wrote: post #22
baddox wrote: post #17

Earlier quoted context omitted.

> I'm fairly certain that cooperating to raise your own offspring is still considered selfish behavior. Why? Because it leads to more descendants? In that case, the premise is a tautology.

The "individual" in evolutionary game theory is generally considered the gene, not the human. A lot of facts of life - like raising offspring at all, or death - make zero sense if you consider the actor to be a person, but make a lot of sense if you consider the actor to be a gene.

I'm aware of the gene-centered view of evolution, but I think that interpretation of the sentence in question is quite a stretch. If that was the intended meaning, then I apologize.

Re: 'Snowdrift' game tops 'Prisoner's Dilemma' in explaining cooperation (2007)

#60

Post by mannykannot »

Danihan wrote: post #45
majewsky wrote: post #40

Earlier quoted context omitted.

A good reputation score would start out at +/- 0 and not punish you for being the lone righteous guy in an otherwise immoral neighborhood.

It does, no one really has a net worth one way or another when they are a child. Define righteous? Define immoral? Capitalism rewards providing actual value to people. It doesn't reward shallow niceties and self-righteousness, those are common.

> no one really has a net worth one way or another when they are a child.

The net worth of one's parents makes quite a difference in practice.

That includes things like being born with a right of residence in a developed, stable country vs. in a refugee camp in a war-torn part of the world.

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