Slashdot Mirror
Humans Can Still Out-Bluff Machines
Pcol writes "The New York Times reports that in a poker game this week between man and machine, a program called Polaris fought a close match, but lost to two well-known professional poker players. Designing a poker playing algorithm is a different and more difficult challenge for software designers than chess and checkers because of uncertainties introduced by the hidden cards held by each player and difficult-to-quantify risk-taking behaviors such as bluffing. The game-tree approach doesn't work in poker because in many situations there is no one best move and a top-notch player adapts his play over time, exploiting his opponent's behavior. Polaris build a series of "bots" that have differing personalities or styles of play, ranging from aggressive to passive. Researchers monitored the performance of three bots and then moved them in and out of the lineup like football players."
let's see how well those computers do in strip poker!
Bite my shiny metal ass.
If you're playing cards in Hold'em, against decent players, you WILL lose.
Hold'em is all about betting - if, when, and how much. And THAT you determine by the behavior of your opponent. It's not a strategy game, but a psychological exercise.
Dealer: My deal..
Eliza: What does that suggest to you?
Dealer: It suggests I'm giving you your cards.
Eliza: We can talk about me later. Now back to you...
Guest: Here you go.
Eliza: So you feel I go...
Guest: Um.. yeah. How many cards do you want?
Eliza: What else comes to mind when you ask that?
Dealer: You need to give me whatever cards you want to exchange.
Eliza: I see. Tell me more.
Dealer: Um.. so you can get a better hand?
Eliza: We were discussing you--not me.
Dealer: Do you have any interest in playing this game?
Eliza: Oh, I have any interest in playing this game?
Dealer: That's it, I quit! Go find someone else to torture!
Eliza: That would't help much, now, would it?
Slashdot Burying Stories About Slashdot Media Owned
Because there's more to a situation than your cards. There's your chip stack, your blinds, the action behind you, your opponents chip stacks, the payment structure, and your position. Pushing on 8-3 unsuited is a poor move, but there's at least two situations where it's called for- if you're far from a money boundary in the payment structure, have a small number of chips in compared to the blinds (say an M of 3-5), and all players before you folded. In this case, by pushing in you're likely to win the blinds. Especially if none of your remaining opponents have a big stack. The risk can be worth it, since it makes absolutely no difference what hand you go out on unless you reach a new money boundary, and you'll have to win at least 1 hand to do so. And with 83, you're likely to have 2 live cards if called by a high ace (AK, AQ, AJ, AT). Note that you'd only want to do this if first into the pot- someone who called the blind is too likely to call you for only an additional 2-4 big blinds.
The other situation to try it in is a squeeze play- if you have a raise and a call behind you, you have a very tight table image, and you think they don't have good hands. A raise, especially an all in raise, is signaling an extremely good hand. From a tight player, this must be respected. You can get both players to fold here if they don't have premium hands (AK, QQ-AA). This is a high risk move though, and you must have been playing extremely tight, versus people capable of laying down a good hand, to try it.
I still have more fans than freaks. WTF is wrong with you people?
Simple bluffs are pretty straightforward to handle, but the combination of factors in poker (multiple rounds of action, shifting hand strength, complex unknown information) makes it inordinately difficult to compute Von Neumann optimal strategies. Even simpler games like (0,1) poker (both players are randomly 'dealt' a number in the 0..1 range, smallest number wins) with multiple betting rounds are remarkably difficult to solve under normal betting patterns. For more information, I heartily recommend The Mathematics of Poker by Chen and Ankenman.
That's what they want you to think.
Look at the first entry (bottom of page) on the Polaris team's blog for the second day. The day that the humans started winning:
e /Live/Day2Session1/
http://www.cs.ualberta.ca/~games/poker/man-machin
The U of A team gave the humans the logs of the first two games!
Perhaps after the entire match they could have reviewed the game logs, however this give the humans an unfair advantage during the second day. I can't believe that this isn't getting more attention -- they bascially gave the human team a huge insight into the inner workings, strategy, and tendencies of their opponent. Something that Polaris definitely did not have.
In my opinion this sours the competition and completely invalidates the final two matches. The human likely found a weakness (or two or three) and exploited it, and we can't know for sure that they would have found the weakness without those logs.
That was a huge mistake by the U of A team, and they have apparently got away with it without anyone noticing.
Being that the CS folks that setup the computer were expecting a draw, I think they must have started with the assumption that a top level pro poker player knows the statistics of almost every situation (from experience and intuition) as well as a machine can calculate them. And the truth is they do - the best probably know what their hole cards and flop mean down to the first decimal point every single time it's worth thinking about.
So, then the play comes down to responding to how the other person is playing. And the edge goes to the one that can safely be unreadable/unpredictable/inconsistent.
Now, obviously if you can't figure out any of the statistics involved in a hand you will always get your ass handed to you in the long run by a player/machine that can do the most rudimentary calculation.
Getting diabetes AND salmonella would be a bad weekend.