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."

Comments

Re:Not harder than chess

[TheMeuge]

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.

stratego, l'attaque, dover patrol, tri-tactics etc

[hedley]

Games with imperfect information. Very hard to design good AI to play these games, as the story says, tree search is not a win here. A game like stratego also has concepts that go beyond individual piece movement, i.e. you may want to group an few pieces together to make an attack, moving the unit (subject to input from the enemy) forwards. I have yet to see a good stratego game, there is one for $ called "The General". It can be defeated quite easily. I have found a stratego game in the past that could *not* be defeated! But, some sleuthing on my part (via saving the game and restoring it at key points) showed the sw was cheating by moving its pieces around to adjust to the threats(!). I have had an obsession with this style of AI but its such a daunting problem its hard to get a good handle on where to start to chip away at it. I suspect the polaris folks have been doing just this, the AI and methods they develop would be useful for other games I am sure.

H.

Re:Not harder than chess

[c_jonescc]

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.