Stigma wrote on 06/07/13 at 02:32:35:
In your candidate move list, the differences in evaluation are small enough that they may not matter much in a human game.
Second, shouldn't it be possible to get engines closer to human play (at some cost to playing strength, obviously)? Human biases are well-known and books have been written about them (Afek/Neiman: Invisible Chess Moves). So you could assign lower values to backward bishop moves, moves that put more than two pieces en prise, wrecked pawn structures, moves that leave most of one's pieces undefended, material compared to piece activity (since humans are worse at consolidating against an initiative); higher value to king safety and healthy pawn structures etc.
My list was regarding Mr. Ivanov specifically; in his prior games, he consistently played the top choice of Houdini in boring endgames where the differences between the top 5 moves was similar to what I wrote. That's extremely improbable to do in a single game, but multiple games?
And I suppose we can program in a little "human bias" in the evaluation algorithm, sure. But computers don't think like humans, and they're
still going to play those weird computer moves that hang on a tactical nuance 16 ply deep that a human would never have considered in the first place. If that tactical nuance is enough to win a piece--or even just a whole pawn--it's going to overwhelm the minor "human biases" of an extra -0.2 that we programmed in for having a backward pawn, etc.
Besides, the reason that computers play as well as they do is that we already have programmed in those human biases! They evaluate positional compensation much better now than they used to; just fire up your old copy of Fritz 4 and put some positional pawn sacrifices in to see what I mean. But even with the human biases, computers are "seeing" much more than human players do and choosing moves based on odd tactical sequences that a human would never have considered.
This is my professional opinion, for what it's worth. As I mentioned previously, I'm an electronics engineer at the most prestigious astronomical observatory in the world (Keck), and among other things I design "little computer systems." I wouldn't exactly consider myself an expert witness as I'm certainly not a leader in my field, but I think that my former professors and researchers would agree with me in this case.