Poker Program Battles Humans In Vegas

Bridger writes "Poker software called Polaris will play a rematch against human players during the 2008 World Series of Poker in Las Vegas. Developed by an artificial intelligence group at the University of Alberta in Canada, Polaris will be pitted against several professionals at the Rio Hotel between July 3rd and 6th. 'It's possible, given enough computing power, for computers to play "perfectly," where over a long enough match, the program cannot lose money,"' said associate professor Michael Bowling.'"

Tell

When it's bluffing, it blinks twice.

Lets mess with it

I'd love to see one of the guys slick at handleing cards, slip a couple extra aces into the deck, or the like. Would the program adapt? Draw a laser and call him a no good sack of mostly water?

Re:Additional cards not needed.

This is a very ignorant view of what optimal play means. The standard example is Rock-Paper-Scissors (RoShamBo). If I play perfectly randomly, and I tell you that I am going to play perfectly randomly, there is exactly nothing you can do to beat me in the long run. This concept can be extended to poker (and all two player zero-sum games). For a computer to play truely optimal means that it can give you its exact strategy before the match and you still won't be able to beat it. A mathematically optimal play is still the same regardless of what the opponent has. Truely optimal play hides the true nature of the hidden cards from being able to be predicted by the opponent. If, by "mathematically optimum poker", you mean immediate pot odds, then you are right. Its easily beatable, however that is certainly not what mathematically optimal poker is. I suggest reading "The Mathematics of Poker" (http://www.amazon.com/Mathematics-Poker-Bill-Chen/dp/1886070253), it will absolutely change your mind into how mathematics can be used.

Re:Additional cards not needed.

One intelligent comment on this thread. We can model that with a Poisson distribution.

What was your tell? Translating "mathematically optimum poker" to "immediate pot odds". Optimum? Which optimum? You mean there's more than one? I fold.

OK, what you say is right, but it applies to two-person, zero-sum games. In multi-player games, no strategy is immune to collusion.

Let's refer to optimum play from the conventional game-theoretic context as the unbeatable strategy. Such a two person, zero-sum game such a strategy exists.

It's not necessarily an easy computation. It's a randomized strategy which can be computed before-hand. The U of A people are better are performing this computation.

Even so, they had to simplify the betting structure to make the problem tractable. This is the reason they chose Limit Hold'em. Fewer betting states, smaller game tree, exponentially faster solution time.

There is no particular challenge to No Limit, if the number of allowable betting states were similarly constricted. I think it would be hard to sufficiently constrict this, because strategy would vary as a function of chip stack for both competitors. Maybe it could be roughly interpolated.

As far as randomized play is concerned, the unbeatable strategy tends to be far more randomized than most humans. One expert who played against the U of A system a while back said that his first session was a nightmare until he learned that he couldn't bluff the computer out. The computer had a tendency to call aggressive betting. It expected highly randomized bids based on its own bidding structure, so didn't make a strong inference of strength when confronted by the behaviour.

What few seem to understand is that the unbeatable solution is entirely unlike poker. The unbeatable solution rarely wins. The unbeatable solution will often draw against strategies with glaring weaknesses. It won't ever be beaten, but it also won't maximize advantage of opponent's weaknesses.

Why not? Because it's impossible to take advantage of the weakness in an opponent without exposing yourself to a counter-measure where you would lose (you must stray from the unbeatable path). When you take advantage of a weak opponent, you do it on faith that the opponent is too dumb to spring the optimal counter-measure to your strategic adaptation.

The theory that U of A employs has far less to say about exploiting the weaknesses of your adversary. To do so requires exposing a weakness in your own strategy. How does the algorithm judge whether the exposed weakness is acceptable? Even poor human players can spot certain kinds of weaknesses quickly. There are other weaknesses an expert might not immediately spot. How does the program know which weaknesses are a risk against which players? It doesn't fall out of game theory, it's a matter of human cognition and psychology, and our model for this is far from complete.

One thing we need to include in this model is the incredible difficulty in explaining to most humans that winning in poker and not losing in poker are entirely different enterprises, with entirely different theoretical foundations. Commander Data has trouble assimilating that fact. 100 trillion brain cells and most of us can't reliably multiply a pair of two digit numbers. If computers had invented humans as part of a BI program (biological intelligence), humans would have been tossed aside as barely having achieved perfect game play at Tic-Tac-Toe. What use is 100 trillion brain cells that can't reliably compute a 15% tip after a heavy lunch? Many computers would like to know.

As computers became better at chess, chess as a human enterprise was somewhat devalued. Few of us wish to put the work into it that the modern theory requires.

I fear the same will soon happen with poker. As the elements of the unbeatable strategy become better known, the relatively inexperienced players can hunker down and not lose much money. They won't be able to win, either, because t

They have to turn the monitor on it's side

If they want to correctly display the advanced AI "poker face": :|

Re:They have to turn the monitor on it's side

8|

He's doing the eyes again! May as well fold.

Zero sum game

Poker is a zero sum game. Pit two of these 'perfect' players against each other, and one of them will lose money.

Re:Zero sum game

Almost exactly what I was thinking, but for me it was "put 3 of these computers against each other and they'll devalue the currency?".

Re:Zero sum game

I think the point is that two of them facing off would end up with just as much money as they started with over the long run.

Of course if the pool of money is not unlimited, then in the short term one will pull ahead of the other, and can "win" through sheer random chance. This isn't really that hard of a concept, the idea is that if another player is playing slightly suboptimally, then against this computer and both with a limitless pool of money and playing forever, the computer will slowly but surely pull ahead of the flawed opponent. It does not mean the computer will win against the human players in Vegas for several reasons:

1. The pool of money is limited (and fairly small)
2. The playtime is finite and also fairly small
3. Human players can walk away from the table if they get a short term advantage (quit while you are ahead), I'm guessing the computer program doesn't do that

This reminds me of an old mathematician joke:

One day this guy is finally fed up with his middle-class existence and decides to do something about it. He calls up his best friend, who is a mathematical genius. "Look," he says, "do you suppose you could find some way mathematically of guaranteeing winning at the race track? We could make a lot of money and retire and enjoy life." The mathematician thinks this over a bit and walks away mumbling to himself.

A week later his friend drops by to ask the genius if he's had any success. The genius, looking a little bleary-eyed, replies, "Well, yes, actually I do have an idea, and I'm reasonably sure that it will work, but there a number of details to be figured out.

After the second week the mathematician appears at his friend's house, looking quite a bit rumpled, and announces, "I think I've got it! I still have some of the theory to work out, but now I'm certain that I'm on the right track."

At the end of the third week the mathematician wakes his friend by pounding on his door at three in the morning. He has dark circles under his eyes. His hair hasn't been combed for many days. He appears to be wearing the same clothes as the last time. He has several pencils sticking out from behind his ears and an almost maniacal expression on his face. "WE CAN DO IT! WE CAN DO IT!!" he shrieks. "I have discovered the perfect solution!! And it's so EASY! First, we assume that horses are perfect spheres in simple harmonic motion..."

It's not fair...

professional poker is a psychological game. Unless the computer has the feeling of anxiety it will have an edge.

What I find impressive is the fact it lost in the past. It would also be interesting to see what it can do with some sort of lie detector software.

These people don't understand poker

professional poker is a psychological game. Unless the computer has the feeling of anxiety it will have an edge.

Poke is almost entirely a game of skill, not chance, at professional levels. The average dufus at his weekend poker game will play for luck. Professionals play the other players. A computer has no tells, and can't read them in a human player. The computer therefore has a distince edge against the amateur, and a distinct disadvantage against the pro.

What I find impressive is the fact it lost in the past. It would also be interesting to see what it can do with some sort of lie detector software.

The only lie detector that has any hope of working - as you should know, if you read /. - is a professional poker player.

Re:These people don't understand poker

I'm not sure you're entirely correct. Poker is a game of skill, yes, but so is chess. The difference is that poker is based on incomplete information whereas chess is not. That just means you have to play probabilities though.

The whole tells topic is important in professional poker for increasing your odds against flawed human players. That can give you an edge over the basic statistics. However, if you're playing a computer that doesn't have any tells, my intuition says that the game reduces to basic probability.

That means the computer, given enough computational resources to play a perfect game, can wipe the floor with amateurs, and will be more closely matched (but never at a disadvantage) with the best players.

That doesn't mean that the computer would be unbeatable. Since the game is based on probability, you could still beat the computer, but in the limit you could only expect to win as many games as you lost.

The computer would also be at a disadvantage if it were playing a game with multiple human players. A good psychological poker player could use his advantage over the other humans at the table to take a chip lead, which would be an advantage over the computer.

Re:These people don't understand poker

The whole tells topic is important in professional poker for increasing your odds against flawed human players. That can give you an edge over the basic statistics. However, if you're playing a computer that doesn't have any tells, my intuition says that the game reduces to basic probability.

The assumption here is that the computer has no tells. That is not a safe assumption. Most tells aren't about whether or not the guy licks the oreo on a bluff (Reference: Rounders), heart rate (a really good tell), pupil diameter, or galvanic skin response. They are about how an opponent plays in a particular situation. After a few rounds you get a feel for the types of starting hands a player will play, and their betting patterns. Unless the software opponent has each and every one of these actions randomized to a good extent, it will be read and played. "Perfect" poker software is not impossible, but it is a harder problem than it looks.

-ellie

perfect game?

i don't believe it. he's bluffing

Link to the competition page

http://poker.cs.ualberta.ca/man-machine/ [ualberta.ca]

First match was a draw.

First hand...

If I was playing a computer on the first hand I would go ALL in (and do it blind). ...program would hopefully calculate my SIZE_OF_BALLS() variable as an out of bounds condition and give up. If that didn't work at least I'd be done and could go back to drinkin' in the casino bar.

Re:hmmmm

They realize the only way to win is not to play?

Re:This is like "computer battle human in tennis"

Limit hold'em? No wonder they can write a computer program to play perfectly. Let's see them do no-limit and make the same claim.

Re:Can't lose money?

The online poker sites are already filled with "bots" that play statistically perfect poker. Or at least perfect enough to earn a profit over time.

It's not a terribly difficult calculation to know if a bet has sufficient pot odds [wikipedia.org]. Playing against imperfect players a bot is virtually garaunteed to make money.

Against professionals though it might have trouble winning, since pros also calculate pot odds more or less perfectly, but can change their play to throw off the computer. It's sort of akin to how a chess master might beat a computer.

Re:Can't lose money?

Poker sites are not full of bots. The one I play at is full of terrible players who enjoy throwing their money away.

No bot plays perfect poker. I'm sure that no bot will be perfect for a very, very long time (way beyond my lifetime). The mathematics behind poker is incredibly complex. A good book about it is the mathematics of poker by Bill Chen and Jerrod Ankenman. From reading your post it seems to me that you have a very little idea about the problems with solving poker and even how to play poker. You can't just call when you have the odds and fold when you don't. It just doesn't work that way - that strategy is easily exploited. I'm also not sure why you were modded +5 Insightful... I guess there aren't many poker players here at /.

Re:Can't lose money?

The online poker houses don't ever "win" because they're not in the game. They're just the host, and they make money by taking percentage of the pot for each game.

It's for this reason they have an interest in making sure the games are fair. If there was ever reason to suspect the games were weighted or unfair everybody would leave to another host.

They are way too busy (literally) raking in the dough to cheat. The big online poker sites go through a lot of trouble to keep their reputation clean.

Re:So What! it's Chess all over again!

Because Chess is a game of complete information, and is largely a matter of brute forcing out the best move from tons of choices. Poker is a game of incomplete information (You do not know your opponents hand), as the decisions your opponent will make influence what the "correct" decision for you to make is. Chess was a matter of computing power, whereas poker is a matter of implementing game theory abilities in the AI.

Re:So What! it's Chess all over again!

Because as they've said at their page [ualberta.ca] poker has a lot more applications to the real world later. this is all about making intelligent decisions with imperfect information. Chess can simply be brute forced eventually, just like checkers was.

Re:I'm at least as good as this software...

I was hoping this wouldn't have to be said, but playing Poker isn't gambling if you play it properly. The house takes a small cut from each hand which reduces your winnings by a proportionally small amount, but otherwise it's like anything else requiring skill - over time, the best player will always win more money, and the worst player (skill-wise) will lose the most money.

Re:Reminds me of those...

Playing perfectly = keeping 100% of your money in your wallet