Chinese scientists create winning theory on Rock-Paper-Scissors

[TaiShang]

Chinese scientists create winning theory on Rock-Paper-Scissors
2015-01-27

The schoolyard game of Rock-Paper-Scissors doesn't seem like one in which players take a scientific approach.

But that is exactly what three Chinese scientists discovered, and their findings were published in a research paper that won them a Best of 2014 by MIT Technology Review, published at the prestigious Massachusetts Institute of Technology in Cambridge.

Wang Zhijian and Xu Bin of the Experimental Social Science Laboratory at Zhejiang University, and Zhou Haijun of the Institute of Theoretical Physics of the Chinese Academy of Science wrote a paper called Social Cycling and Conditional Responses in the Rock-Paper-Scissors Game.

"It is the first time Chinese scientists won this prize in the social science realm," according to a statement by Zhejiang University in Hangzhou.

Their research revealed a pattern of choices players make during the game.

Players randomly choose each action about a third of the time in the first round. However, in later rounds, players who win tend to stick with the same action, while those who lose always switch to the next action in a clockwise direction going from rock to paper, paper to scissors, or scissors to rock. The pattern is also summarized as "win-stay, lose-shift" in the paper.

To win, players need to pay attention to what their opponent just did. Then they can estimate how their opponents will act next, and throw the hand to beat the move.

If a player wins by playing rock, he is very likely to play rock again in the next round. But if he loses, he will most likely switch to paper in the next round.

This is known in game theory as a conditional response and has never been discovered before in game experiments, according to MIT Technology Review.

"This game exhibits collective cyclic motions, which cannot be understood by the Nash Equilibrium concept (which postulates that players randomly complete their actions to avoid being exploited), but are successfully explained by the empirical data-inspired conditional response mechanism," according to Wang.

To find the pattern, researchers recruited 360 students at Zhejiang University for the experiment. Participants were divided into 60 groups of six players. Students in each group played 300 rounds against each other, and their actions were recorded.

The theory was also selected in the Science News Highlights of 2014 by BBC News on Dec 24. The paper also has been published by Scientific Reports, an online open-access scientific journal, according to Zhejiang University.

 

[WAJsal]

Don't you think it would be much better for the world,if scientists spend their time on some thing more productive.

 

[Levina]

Don't you think it would be much better for the world,if scientists spend their time on some thing more productive.

Game theory helps in understanding pattern of choices.

 

[Lord ZeN]

Not fair
Even i used to make many theories regarding the best way to win Rock-Paper-Scissors. But nobody recognized it at that time.

 

[WAJsal]

Game theory helps in understanding pattern of choices.

This theory is old,if i'm not mistaken i read something like this a year ago,this is just excessive research.

 

[Levina]

This theory is old,if i'm not mistaken i read something like this a year ago,this is just excessive research.

Just because you and me dont understand the subject in depth, doesnt mean there should not be any research made in this field.
We 're being regressive here.

 

[TaiShang]

But that is exactly what three Chinese scientists discovered, and their findings were published in a research paper that won them a Best of 2014 by MIT Technology Review, published at the prestigious Massachusetts Institute of Technology in Cambridge.

 

[WAJsal]

Just because you and me dont understand the subject in depth, doesnt mean there should not be any research made in this field.
We 're being regressive here.

It would be much better for the world ,if they spend their time on topics such as drought,global warming but i guess they are too busy cracking rock,paper and scissors.

 

[Beast]

It would be much better for the world ,if they spend their time on topics such as drought,global warming but i guess they are too busy cracking rock,paper and scissors.

Looks like sourgrape.

This theory is old,if i'm not mistaken i read something like this a year ago,this is just excessive research.

Yes, the prestige US institute is pure dumb to award something. Fault doesn't lies with Chinese team but a prestige US institute decide to award on a theory some deem is useless or widely known by others.

 

[WAJsal]

Looks like sourgrape.


Yes, the prestige US institute is pure dumb to award something. Fault doesn't lies with Chinese team but a prestige US institute decide to award on a theory some deem is useless or widely known by others.

US institute............enough said

 

[TaiShang]

How to Win at Rock-Paper-Scissors

The first large-scale measurements of the way humans play Rock-Paper-Scissors reveal a hidden pattern of play that opponents can exploit to gain a vital edge.

If you’ve ever played Rock-Paper-Scissors, you’ll have wondered about the strategy that is most likely to beat your opponent. And you’re not alone. Game theorists have long puzzled over this and other similar games in the hope of finding the ultimate approach.

It turns out that the best strategy is to choose your weapon at random. Over the long run, that makes it equally likely that you will win, tie, or lose. This is known as the mixed strategy Nash equilibrium in which every player chooses the three actions with equal probability in each round.

And that’s how the game is usually played. Various small-scale experiments that record the way real people play Rock-Paper-Scissors show that this is indeed the strategy that eventually evolves.

Or so game theorists had thought. Today, Zhijian Wang at Zhejiang University in China and a couple of pals say that there is more to Rock-Paper-Scissors than anyone imagined. Their work shows that the strategy of real players looks random on average but actually consists of predictable patterns that a wily opponent could exploit to gain a vital edge.

Zhijian and co carried out their experiments with 360 students recruited from Zhejiang University and divided into 60 groups of six players. In each group, the players played 300 rounds of Rock-Paper-Scissors against each other with their actions carefully recorded.

As an incentive, the winners were paid in local currency in proportion to the number of their victories. To test how this incentive influenced the strategy, Zhijian and co varied the payout for different groups. If a loss is worth nothing and a tie worth 1, the winning payout varied from 1.1 to 100.

The results reveal a surprising pattern of behavior. On average, the players in all the groups chose each action about a third of the time, which is exactly as expected if their choices were random.

But a closer inspection of their behavior reveals something else. Zhijian and co say that players who win tend to stick with the same action while those who lose switch to the next action in a clockwise direction (where R → P → S is clockwise).

This is known in game theory as a conditional response and has never been observed before in Rock-Paper-Scissors experiments. Zhijian and co speculate that this is probably because previous experiments have all been done on a much smaller scale.

“This game exhibits collective cyclic motions which cannot be understood by the Nash Equilibrium concept but are successfully explained by the empirical data-inspired conditional response mechanism,” say Zhijian and co.

In fact, a “win-stay, lose-shift” strategy is entirely plausible from a psychological point of view: people tend to stick with a winning strategy.

Zhijian and co hope to investigate this psychological aspect in more detail in future studies. An interesting question is how this kind of response is “built in” to the brain. “Whether conditional response is a basic decision-making mechanism of the human brain or just a consequence of more fundamental neural mechanisms is a challenging question for future studies,” they say.

The discovery also has practical implications. If humans inevitably use a predictable strategy when playing Rock-Paper-Scissors, that’s a weakness that can be exploited. “Our theoretical calculations reveal that this new strategy may offer higher payoffs to individual players in comparison with the NE mixed strategy,” they say.

That might be worth bearing in mind the next time you take on all comers at your local watering hole.

Ref: [1404.5199] Social cycling and conditional responses in the Rock-Paper-Scissors game Social Cycling And Conditional Responses In The Rock-Paper-Scissors Game

 

[WAJsal]

How to Win at Rock-Paper-Scissors

The first large-scale measurements of the way humans play Rock-Paper-Scissors reveal a hidden pattern of play that opponents can exploit to gain a vital edge.

If you’ve ever played Rock-Paper-Scissors, you’ll have wondered about the strategy that is most likely to beat your opponent. And you’re not alone. Game theorists have long puzzled over this and other similar games in the hope of finding the ultimate approach.

It turns out that the best strategy is to choose your weapon at random. Over the long run, that makes it equally likely that you will win, tie, or lose. This is known as the mixed strategy Nash equilibrium in which every player chooses the three actions with equal probability in each round.

And that’s how the game is usually played. Various small-scale experiments that record the way real people play Rock-Paper-Scissors show that this is indeed the strategy that eventually evolves.

Or so game theorists had thought. Today, Zhijian Wang at Zhejiang University in China and a couple of pals say that there is more to Rock-Paper-Scissors than anyone imagined. Their work shows that the strategy of real players looks random on average but actually consists of predictable patterns that a wily opponent could exploit to gain a vital edge.

Zhijian and co carried out their experiments with 360 students recruited from Zhejiang University and divided into 60 groups of six players. In each group, the players played 300 rounds of Rock-Paper-Scissors against each other with their actions carefully recorded.

As an incentive, the winners were paid in local currency in proportion to the number of their victories. To test how this incentive influenced the strategy, Zhijian and co varied the payout for different groups. If a loss is worth nothing and a tie worth 1, the winning payout varied from 1.1 to 100.

The results reveal a surprising pattern of behavior. On average, the players in all the groups chose each action about a third of the time, which is exactly as expected if their choices were random.

But a closer inspection of their behavior reveals something else. Zhijian and co say that players who win tend to stick with the same action while those who lose switch to the next action in a clockwise direction (where R → P → S is clockwise).

This is known in game theory as a conditional response and has never been observed before in Rock-Paper-Scissors experiments. Zhijian and co speculate that this is probably because previous experiments have all been done on a much smaller scale.

“This game exhibits collective cyclic motions which cannot be understood by the Nash Equilibrium concept but are successfully explained by the empirical data-inspired conditional response mechanism,” say Zhijian and co.

In fact, a “win-stay, lose-shift” strategy is entirely plausible from a psychological point of view: people tend to stick with a winning strategy.

Zhijian and co hope to investigate this psychological aspect in more detail in future studies. An interesting question is how this kind of response is “built in” to the brain. “Whether conditional response is a basic decision-making mechanism of the human brain or just a consequence of more fundamental neural mechanisms is a challenging question for future studies,” they say.

The discovery also has practical implications. If humans inevitably use a predictable strategy when playing Rock-Paper-Scissors, that’s a weakness that can be exploited. “Our theoretical calculations reveal that this new strategy may offer higher payoffs to individual players in comparison with the NE mixed strategy,” they say.

That might be worth bearing in mind the next time you take on all comers at your local watering hole.

Ref: [1404.5199] Social cycling and conditional responses in the Rock-Paper-Scissors game Social Cycling And Conditional Responses In The Rock-Paper-Scissors Game

It is of no use if every one knows the pattern.

 

[thesolar65]

Well, this years "Ig Nobel" is theirs for sure!!

 

[FairAndUnbiased]

I've come up with a bunch of theories on how to win games of chance, like poker, rock paper scissors, etc. However, I've never quantitatively put these theories in terms of a paper lol.

 

[Levina]

It would be much better for the world ,if they spend their time on topics such as drought,global warming but i guess they are too busy cracking rock,paper and scissors.

lolzz
What would happen if every country forces its scientists to research only in certain areas???
You know the answer am sure.

I dont intend to continue this further for I think its futile.
Thank you!