From: sloan@cis.uab.edu (Kenneth Sloan)
Subject: Re: computers that intentionally slip up (was Re: chinook)
Keywords: update
Organization: CIS, University of Alabama at Birmingham
Date: Fri, 28 Aug 1992 15:37:40 GMT

In article <1992Aug28.064606.22271@ists.ists.ca> sizone!justin@ee.ryerson.ca (Justin) writes:
>In article <1992Aug28.010326.16786@cis.uab.edu> hyatt@cis.uab.edu (Robert Hyatt) writes:
>>In article <21189@optima.cs.arizona.edu> rcs@cs.arizona.edu (Richard Schroeppel) writes:
>
>>...
>>    Shouldn't the program say "wait a minute, I will get
>>mated in 11 or else sac my queen, but, I don't think an 1800 player
>>can find this mate...  since I'm gonna sac my queen, I'll probably
>>lose anyway, so I'll take the rook and run (and hope...)"
>
>While I am compelled to admit that this might result in the program
>winning a few more games...
>
>I have to say I have always strongly opposed the argument that says the
>superior players should intentionally make a mistake on the presumption
>that the inferior player won't catch them.  
>

Careful now - this is tricky.  First, it's not necessarily the case that
playing into the 11-move mate is a "mistake".  The alternative of
playing on down a queen with no compensation is equally lost.  The fact
that you can't see the mate in the latter line doesn't mean that it
isn't there!  Essentially, this is a subtle version of the classic
'horizon effect'.

>Perhaps my argument doesn't apply to computers so readily, since the
>main thrust is to claim it is a bad habit, and leads to careless play.
>However, something still bothers me about the whole idea of this.  I
>would rather play my best possible game, and lose; than make a move I
>know is wrong and win.  I get no satisfaction out of such "victories".

I agree that many human players carry this idea too far - but...this is
precisely the kind of play which (ought to?) characterize human play of
the game, mind against mind, as opposed to mechanical search for the
'best moves'.  The relevant aphorism is "Don't waste a $5 play on a
nickle opponent".  I'm reminded of the novice soccer goalie who stuffed
a veteran attacker.  Later the attacker complimented the goalie on seeing
through his beautifully executed fakes.  The novice replies "What fakes?
I just came out and jumped on the ball."

One of the central lessons of AI research on natural language
communication is that participants in a conversation must attempt to
model the computational powers of their partner in the conversation.
Provide too much detail and you insult someone's intelligence; assume
too much and you lose your audience.  Playing two-person games (in the
human sense, not the game theoretic sense) is a conversation.  Any fool
can play the best moves when they lead to a win.  It takes a bit more to
look for practical chances in a position that you know is lost - or
where it is necessary to choose between competing 'unclear' lines.

In other words - it's harder, and more interesting, to play
like Tal than it is to play like Karpov.

Finally, consider what *you* would have done in the initial situation:
assume that you see the very sharp line leading to mate in 11.  Would
you:

    a) play the line anyway, hoping for a mistake?
    b) give up a Q, for no compensation, leading to a game
       that you ae moraly certain is a dead loss?
    c) simply resign (isn't that, after all, the 'correct' move?)

-- 
Kenneth Sloan                   Computer and Information Sciences
sloan@cis.uab.edu               University of Alabama at Birmingham
(205) 934-2213                  115A Campbell Hall, UAB Station 
(205) 934-5473 FAX              Birmingham, AL 35294-1170
Newsgroups: rec.games.chess