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Janken (rock-paper-scissors) Robot with 100% winning rate
June 26, 2012 10:20 PM   Subscribe

"The purpose of this study is to develop a janken (rock-paper-scissors) robot system with 100% winning rate as one example of human-machine cooperation systems."

Of previous rock-paper-scissors interest on metafilter.
posted by SpacemanStix (34 comments total) 5 users marked this as a favorite

 
not sure the significance of this. Lots of things are faster than human consciousness. Clearly the "robot" is throwing after the human commits so it is not a contest.
posted by pdxpogo at 10:26 PM on June 26, 2012 [2 favorites]


Yeah, I think the robot cheats by delaying its response for about 200 milliseconds until it recognizes the hand gesture initiated by its human opponent. Humans can't counteract an initiated response in that small a time frame, so it's a pretty easy win for the robot.

That said, I do enjoy giving robots the finger.
posted by twoleftfeet at 10:28 PM on June 26, 2012


I always feared this day would come.


And now I have to quit playing rock-paper-scissors with robots.
posted by mazola at 10:39 PM on June 26, 2012 [3 favorites]


So, we need our AIs to cheat faster and better than before?

Paging Blizzard! BLIZZARD TO THE WHITE COURTESY PHONE PLEASE!
posted by Samizdata at 10:39 PM on June 26, 2012 [4 favorites]


It's an interesting contrast though in how to win at Rochambo (that's what they call Rock-Paper-Scissors in educated circles. Unless they are really sophisticated, in which case they spell it Rochambeau.)

Really good players - I mean human players - tend to rely on something completely different; the fact that humans are terrible at generating randomness. Winning at Rock-Paper-Scissors becomes a study in human psychology.

For example, males have the tendency to produce rock on their first throw, at least according to this infographic. There is something deeper going on there than "simple" gesture recognition.

If you really understand the psychology, you can increase your win rate beyond 50-50. But 100% win rate requires cheating, in some sense.
posted by twoleftfeet at 10:53 PM on June 26, 2012


Iocaine Powder is a much more interesting RPS AI program. The source code is worth a look.
posted by painquale at 11:19 PM on June 26, 2012 [7 favorites]


This robot is cheating, of course. If you want to play against an honest robot, go here.
posted by vidur at 11:20 PM on June 26, 2012 [4 favorites]


I made a post about Slahal a couple years ago, and I'm going to mention it again, because I still think it's one of the most subtle games I've ever seen.

The rules are simple, even childlike. "I have a penny, Bobby. Is it in my right hand or my left hand?"

You can read about Slahal at Wikipedia. It's a game that goes back thousands of years. But it's still played today among the Indians of the Pacific Northwest. I've see them gamble thousands of dollars on the outcome of the game.

I honestly couldn't believe they were doing this when I first saw it. To me, it was like betting on the toss of a coin. The bone is either in the right hand or the left hand, right? So it's a 50-50 chance of winning. But no... some teams consistently win. How is that possible?

You hold the marked bone behind your back. You pass it back and forth with the unmarked bone and then you hold out your hands. One of them has the marked bone, the other has the unmarked one. The opposing team has to guess which hand has the marked bone.

Meanwhile, while the opposing team is trying to guess, your team chants and beats on drums and generally tries to disrupt their cognitive processes. Because your opponents are using every detail they know about you, every eye movement, the slightest change in your facial expression or your body posture, their deepest sense of whether you are ready to win or lose, to try to find the marked bone. And your team has to stop them by the psychological force of their drumming and chanting.

I'd put those guys up against any robot in that game.
posted by twoleftfeet at 11:40 PM on June 26, 2012 [14 favorites]


I have a very good track record when playing rock-paper-scissors against chickens.
posted by mazola at 11:41 PM on June 26, 2012


It can also pick the trifecta 200ms after the race is over. What can't it do?
posted by justsomebodythatyouusedtoknow at 11:54 PM on June 26, 2012 [4 favorites]


I'd put those guys up against any robot in that game.

Even a robot that's got a camera behind their backs, tracing every move of the marked bone?
posted by vidur at 12:11 AM on June 27, 2012


"Hand shape recognition" - ppttthhhh. Just count the number the number of flesh-toned pixels. Fist - low quantity; scissors - medium quantity; paper - high quantity.
posted by Ardiril at 12:28 AM on June 27, 2012 [1 favorite]


They don't show the bones, even behind their backs. No shit. I mean, I've actually stood behind them and watched them do this, and, unless they are really careless, it's not possible to see which hand has the marked bone. (Technically speaking, the opposing team has to discover the unmarked bone, but it's logically equivalent.)

For a robot to win at Slahal, it would have to do way more than simple image processing. It would have to be able to understand the same subtleties that human players use to consistently win the game, and those aren't entirely visual cues; there's a really deep psychological component.
posted by twoleftfeet at 12:29 AM on June 27, 2012


They don't show the bones, even behind their backs. No shit. I mean, I've actually stood behind them and watched them do this, and, unless they are really careless, it's not possible to see which hand has the marked bone.

Ah, ok. Thanks for explaining.
posted by vidur at 12:40 AM on June 27, 2012


First the machines beat us at chess; then Jeopardy, and now rock, paper, scissors... As a gradient that seems sort of... unexpected?
posted by Segundus at 1:02 AM on June 27, 2012 [6 favorites]


I'm going to stop making comments about Slahal, but before I do, I'm just going to say that I wish there was more about this game on the web. There are quite a few videos actually - here's a video of a Slahal match where they cover the bones (or "sticks") with a cloth instead of mixing them behind the back. But there aren't many scholarly publications or news articles about this.

I'm not a Native American. I stumbled onto this by accident. But I went from thinking "this is one of the dumbest things I've seen people do" to thinking "this is one of the most profound things I've seen people do" pretty quickly. It means a lot more to be human than simple descriptions provide.
posted by twoleftfeet at 1:22 AM on June 27, 2012 [5 favorites]


Tic Tac Toe is next. And then it's duck-and-cover time.
posted by Sys Rq at 1:23 AM on June 27, 2012


Yeah, I think the robot cheats by delaying its response for about 200 milliseconds until it recognizes the hand gesture initiated by its human opponent. Humans can't counteract an initiated response in that small a time frame, so it's a pretty easy win for the robot.

I don't know if this page means it detects it in 1 ms, or that's what they are hoping to get. Either way, I think their limiting factor isn't the detection but the squeaky, (relatively) slow moving hand that makes the play afterwards.
posted by Gary at 1:35 AM on June 27, 2012


it detects it in 1 ms

That would be way faster than it needs to be. Overriding Bereitschaftspotential takes about 350 milliseconds, so the Nyquist frequency is only around 175 ms.
posted by twoleftfeet at 2:04 AM on June 27, 2012


Duh. I just remembered that for Rock-Paper-Scissors both competitors are supposed to display their choice at the same time. So the robot would need to effect a choice within 100 ms to appear to be "at the same time". Which means the detect-effect loop has to be much faster.
posted by twoleftfeet at 2:43 AM on June 27, 2012


I misread that as "a jenkem robot system" and let me tell you I'm relieved that I did
posted by DecemberBoy at 3:12 AM on June 27, 2012 [1 favorite]


And your team has to stop them by the psychological force of their drumming and chanting.

I'd put those guys up against any robot in that game.


I'm going to bet on the robot, since they tend not to be distracted by drumming and chanting.
posted by DU at 4:42 AM on June 27, 2012


Against human competition (with the exception of the fierce an powerful Mrs. Ghidorah), I am the junken master. My rock destroys your puny scissors. My paper covers your rock so totally, even the concept of stone having ever existed is lost from human memory. You can't even begin to underestimate the power of my fully operational battle scissors.

I use these powers against my students. I challenge them to high stakes, homework or no homework junken. If their puny champion can defeat my five finger death junken, they won't have homework on that day. The class champion inevitably returns to his defeated classmates in a miasma of shame.

I'm insanely good at it, is what I'm trying to say.
posted by Ghidorah at 5:56 AM on June 27, 2012 [5 favorites]


Damn. There goes the edge-of-the-seat closer for my new Terminator screenplay.
posted by The Bellman at 6:03 AM on June 27, 2012 [1 favorite]


"Hand shape recognition" - ppttthhhh. Just count the number the number of flesh-toned pixels. Fist - low quantity; scissors - medium quantity; paper - high quantity.

Yes, because we all know that science is always that simple and adheres to our intuition.
posted by Evernix at 6:39 AM on June 27, 2012 [1 favorite]


Yeah, the robot isn't playing a game, it's recognizing a gesture. So it's not really winning anything.
posted by one more dead town's last parade at 6:45 AM on June 27, 2012


when robots cheat, everyone loses.
posted by RockyChrysler at 6:54 AM on June 27, 2012 [1 favorite]


Good ol' predictable rock. Nothing beats that.
posted by stevil at 6:56 AM on June 27, 2012


Saw this earlier elsewhere on the net, and there was one commenter's suggestion I liked. Build a second one and force them to play each other.
posted by radwolf76 at 7:04 AM on June 27, 2012


Never Trust Robots! Lyin', cheatin', backstabbin', soulless wretches, every last one of them.
posted by Pirate-Bartender-Zombie-Monkey at 7:21 AM on June 27, 2012


Accomplished. Rock, Paper, Scissors with 100% Win Rate.
posted by Naberius at 7:32 AM on June 27, 2012 [3 favorites]


Tic Tac Toe is next. And then it's duck-and-cover time.
Don't you mean "It's Duck-Duck-Goose time"?
posted by Mister Moofoo at 7:42 AM on June 27, 2012 [1 favorite]


Here's a bunch of other high-speed things this hand can do (from 2009).

Here's the point of this RPS project: if you play with it in person, it's a visceral taste of what it's going to be like when physical objects move at the speed of computers -- "intelligently", yet faster than humans can perceive.

Some examples of where this is going to show up, if robots continue to get faster and smarter:

- A robot that could cheat a different way: decide to play scissors, and then reach out and poke key muscles in your hand so you involuntarily switched from rock to paper. It could then return to its scissor position before you saw what it was doing.

- A robot in kitchens of fancy restaurants that could turn out note-perfect copies of a meal invented by a master chef, in the time it takes for the underlying chemical processes to happen. Imagine the whole back-of-house pyramid replaced by a single robot moving faster than you can see. Instead of picking one restaurant to go to, you can drive through your local Snootyville and select one of the latest creations from great chefs around the world.

- A sniper robot that can fire more accurately than any human, 1000 times a second. Imagine, say, walking safely through a firefight between mere humans, knowing that if-and-only-if someone attempts to point a weapon in your direction, your robot will preempt the attack. Projectiles that somehow get through that round of defense will simply be shot out of the air.

- A surgery robot that is finished suturing the patient by the time the surgeon's finger comes off the "suture" button and before she can say "next patient."

- A tailor robot that finishes modifying your suit in the time it takes to walk from the mirror to the cash register. (Query whether you will have to take the suit off before it does this.)

- A makeup robot that reaches in, applies the makeup of your choice and vanishes in the time it takes you to take the last two steps out of your house. Or a barbershop that looks like an airport metal detector with a couple of robot arms -- choose your haircut, walk through the gate, and by the time you've stepped through your haircut is done. The robot has also removed paper cash from your wallet to pay for your haircut, left itself a fair tip, checked you for weapons or explosives, and thrown in a free vasectomy to thank you for your loyalty.

In short: we are used to computers doubling in speed every 18 months, and doing more and more things faster than we can think. But if anything like the same progress begins to apply to computers' ability to see, reason about, and manipulate the physical world, any number of things become possible that today seem magical. There's obviously some physical limit to how fast robots can move, but I think the speed we already know they're capable of opens up at least some of these "magical" possibilities, lacking only software that we can expect to improve.

So, yes, the robot is cheating at rock, paper, scissors. No, that doesn't mean its ability to beat you every time is unimportant.
posted by jhc at 8:21 AM on June 27, 2012 [4 favorites]


Behold Skippy, The Stone-Skipping Robot
posted by homunculus at 2:48 PM on July 12, 2012


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