Thread

1. janalsncm · 1790977486 · focus · HN ↗

   > The algorithm also learned far faster—it played about 34 times fewer games than DeepNash, and still ended up much stronger.

   Imo, this is the critical piece and what makes the AI work at all.

   With hidden information games, the best move depends on information you don’t have. So a move could be good or bad, it just depends on something that’s impossible to know.

   You’d like to search ahead, meaning “if I do this they will do that” but that’s impossible since you don’t even know what the opponent can do because you don’t know their hidden state.

   If the possible hidden states are randomly distributed, you are screwed. It’s just like rock paper scissors: there’s no best move if your opponent is unpredictable.

   However if you can quickly learn to predict their moves, it becomes possible to make informed decisions about what to do.

   1. williamtell · 1790983167 · focus · HN ↗

      It would be easy enough for a player to be purely random if that was all it took. I think the tension is that piece rank makes some layouts and move strategies more equal than others and calculating the best ones for what has been uncovered so far makes the best layouts not the best layouts.
   2. roenxi · 1790986100 · focus · HN ↗

      In most good full information games, the best move also depends on knowledge you don't have - a full tree of all possible game states from a position. AI playing Go or Chess can't make the best move because they don't know what it is, they're technically just guessing. There isn't any reason to think AI have more or less trouble with hidden information games.

      The practical difference is how many rules a game has and how easy it is to implement the engine. Implementing a chess bot is relatively easy because the amount of state tracking required to set up a simulation is basically nothing (I think just whether the king has made a move yet or not). That makes it easier to implement than something with a lot of signals that need to be recorded. Something like DoTA or Starcraft takes serious engineering effort.

      1. janalsncm · 1790989228 · focus · HN ↗

         You are confusing the inability to compute a full game tree with not knowing anything at all. In fact there are many positions in chess where we can compute the full game tree. Forced mates, and tablebases of positions with 7 pieces or less. And even if we can’t compute the full tree, errors get smaller with depth.

         > There isn't any reason to think AI have more or less trouble with hidden information games.

         How about the fact that a child can beat the best rock paper scissors player in the world in a game, but no human can beat the best chess engine? Same thing with poker, a novice could get lucky and win a hand against the best poker player.

         1. roenxi · 1791005778 · focus · HN ↗

            > How about the fact that a child can beat the best rock paper scissors player in the world in a game, but no human can beat the best chess engine? Same thing with poker, a novice could get lucky and win a hand against the best poker player.

            How about that indeed. What are you trying to say here? The probability of a novice beating an expert doesn't tell us anything except how decisive skill is in a game. We can come up with skilful games where novices sometimes beat experts - in fact, that includes basically all games.

            The point of something like an Elo rating is that on very rare occasions a novice will beat a grandmaster at chess. A human child may well beat the top chess AI on a long enough timescale, we really don't know how that will go. No reason it can't happen. They just have to get really lucky enough times in a row.

            This has nothing to do with perfect or imperfect information. We can come up with a hidden information game where the odds of a novice beating an expert are approximately zero. And we can come up with a perfect information game where experts lose easily (for example, Go has a handicap system to equalise any skill gap).

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