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Prismattic comments on Is Sunk Cost Fallacy a Fallacy? - Less Wrong

19 Post author: gwern 04 February 2012 04:33AM

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Comment author: Prismattic 04 February 2012 05:34:29PM 4 points [-]

novice Go players do things such as adding stones to an already dead group which are clearly identifiable as instances of the sunk cost fallacy,

I don't think this is correct. Novice players keep adding stones because they don't realize the group is dead, not because they can't give up on it.

Comment author: Morendil 04 February 2012 06:12:10PM 6 points [-]

That's probably right at higher kyu levels, when you really have no good grasp of group status.

When you ask a novice "what is the status of this group", though, there is typically a time when they can correctly answer "dead" in exercise settings, but fail to draw the appropriate conclusion in a game by cutting their losses, and that's where I want to draw a parallel with the sunk cost fallacy.

This is similar to life situations where if you'd just ask yourself the question "is this a sunk cost, and should I abandon it" you'd answer yes in the abstract, but you fail to ask that question.

In high-pressure or blitz games this even happens to higher level novice players - you strongly suspect the group is dead, but you keep adding stones to it, playing the situation out: the underlying reasoning is that your opponent has to respond to any move that might save the group, so you're no worse off, you've played one more move and they've played one more.

This is in fact wrong - by making the situation more settled you're in fact wasting the potential to use these plays later as ko threats.

Comment author: AnnaSalamon 06 February 2012 01:27:40AM 6 points [-]

Any idea whether Go beginners' tendency to "throw good stones after bad" results from sunk cost fallacy in particular, or from wishful thinking in general?

Like, is the thought "I don't want my stones to have been wasted" or "I really want to have that corner of the board"?

Comment author: Morendil 06 February 2012 09:52:28AM 6 points [-]

I'd have to look at actual evidence to answer that question with any degree of authority, and that would take more time than I have right now, but I can sketch an answer...

My source of empirical evidence would be the Go Teaching Ladder, where you get a chance to see higher level players commenting on the inferred thought processes of more novice players. (And more rarely, novice players providing direct evidence of their own thought processes.)

Higher level players tend to recommend "light" play, over "heavy" play: a typical expression is "treat this stone lightly".

Unpacked, this means something like "don't treat this stone as an investment that you must then protect by playing further moves reinforcing your conception of this stone as a living group that must be defended; instead, treat this stone as bait that you gladly abandon to your opponent while you consolidate your strength elsewhere".

"Heavy" play sounds a lot like treating a sunk cost as a commitment to a less valuable course of action. It is play that overlooks the strategic value of sacrifice. See here for some discussion.

However, this is usually expressed from an outside perspective - a better player commenting on the style of a more novice player. I don't know for sure what goes on in the mind of a novice player when making a heavy play - it might well be a mixture of defending sunk costs, wishful thinking, heuristic-inspired play, etc.

Comment author: gwern 06 February 2012 01:47:44AM *  1 point [-]

It may be an example of a different bias at play, specifically confirmation bias: they don't realize that the stones are being wasted and can't be retrieved. For example, chess masters commit confirmation bias less than weaker players.

(It's not that the players explicitly realize that there are better moves elsewhere but decide to keep playing the suboptimal moves anyway, because of sunk costs which would be sunk cost bias; it's that they don't think of what the opponent might do - which is closer to 'thoughtlessness'.)