Monday, September 11, 2006

Eye movements: Master vs Amateur

As I start to truly recognize patterns in my mate-in-one problems, I have noticed a new style of looking at the board. I mean this literally. When I see an overall pattern that I think I recognize, my eyes rapidly flick to key squares to make sure it is indeed the right pattern (e.g., is there a bishop on a1 pinning the pawn, which allows mate?). Such rapid, simultaneous eye movements are known as saccades, and we perform many saccades when we read or when we are first confronted with a visual scene, or for that matter when we look at a chess board. The pattern is saccade-->fixate-->saccade again...etc..

Sacaddes do not randomly flick about a visual scene. Psychologists have known for some time that they direct our eyes to locations in the visual environment that are likely to tell us something informative or useful. In a classic study, by Yarbus's group, they monitored subjects' saccades when they were shown a picture of a face, demonstrating that rather than randomly sampling the image, a disproportionate amount of time was spent fixating on certain key features:

It turns out that similar experiments have been performed in chess players. The researchers compared the patterns of saccades in masters versus amateur players. Here is the abstract of the paper:
Expert and intermediate chess players attempted to choose the best move in five chess positions while their eye movements were monitored. Experts were faster and more accurate than intermediates in choosing the best move. Experts made fewer fixations per trial and greater amplitude saccades than did intermediates, but there was no difference in fixation duration across skill groups. Examining the spatial distribution of the first five fixations for each position by skill group revealed that experts produced more fixations on empty squares than did intermediates. When fixating pieces, experts produced a greater proportion of fixations on relevant pieces than did intermediates. It is argued that expert chess players perceptually encode chess configurations, rather than individual pieces, and, consequently, parafoveal or peripheral processing guides their eye movements, producing a pattern of saccadic selectivity by piece saliency.

This is a very interesting study. There is a lot to it, but aside from the obvious stuff, two peculiar facts strike me as interesting. One, masters produced higher amplitude saccades than amateurs. That is, their eyes tend to move longer distances. This is probably because they realize how important it is to consider what is happening long distances from the main action. All chess teachers notice that newcomers to the Game of Kings often miss a long-distance pin when the same students would spot it right away if the pinning piece were adjacent to the pinned piece.

Second, they found that masters fixated on empty squares more often than the amateurs. I am not sure what to make of it, but I know that both Sancho and Tempo have mentioned that as they improve, their focus shifts from material to a more nuanced focus on empty squares as well as filled squares.


Blogger Rocky said...

Very interesting post ... I enjoyed it. I've noticed some similiar things as I'm going through my set of 1000 tactics ... I do find myself beginning to consider the whole board and now, not only am I considering the occupied squares, but the empty ones too.

Obviously CT-ART attempts to train your eyes when you miss a tactic ... it highlights the important squares.

Thanks for the post!

9/11/2006 05:36:00 PM  
Blogger Temposchlucker said...

Interesting stuff. Especially those saccades are new to me.

9/11/2006 07:01:00 PM  
Blogger takchess said...

I may not have this exactly right but once read that as chessplayer develops : He first views the game in terms of pieces, then pawns , then squares

9/12/2006 05:16:00 AM  
Blogger Jim said...

Devil Knight,

One of the reasons the best players stare at empty squares is they are envisioning the moves they are calculating.

As they begin to mentally move the pieces, the spot the squares where the pieces will go to - which is usually an empty square - unless they are doing exchanges - and even then they look to the empty squares to see where enemy pieces could land after there move.

9/13/2006 05:35:00 PM  
Blogger Blue Devil Knight said...

J'adoube: excellent point. I haven't read the full paper yet: it would be interesting to see if they discuss it.

9/13/2006 06:13:00 PM  
Blogger Jim said...


Let me know if they also say the same thing.

My conclusion is based upon anecdotal observations when I discuss games with highly ranked players.

I notice during the conversations they don't discuss material but instead discuss ideas and potential moves - tactical or positional - and invariably we end up talking about the squares where pieces will land for both sides.

I would wager this is the result of strategic training.

9/13/2006 07:12:00 PM  
Blogger King of the Spill said...

Great post. They literally see the whole board quicker. When I try to scan the whole board I can get information overload.

I refer to the empty square focus phenomenon as seeing what isn't there. It reminds me of magnetism . I bet any amateur can get a taste of this by doing mini-circles on a custom set of sacrifice problems. It probably would be easiest if the set was made where the best first move in each problem was a sacrifice on an empty square. After 7 circles of that you probably will look at the board a differently.

I suspect strong players look at an occupied squares differently too; in addition to visualizing exchanges I bet they automatically envision threats that occur when one piece moves off a square so another piece can occupy it on the next turn. That type of thinking doesn't flow easily for me.

9/14/2006 06:00:00 AM  
Blogger Qxh7# said...

You continue to have the most interesting Chess Blog in the Blogosphere. I greatly enjoyed this post.

9/14/2006 03:35:00 PM  
Blogger Blue Devil Knight said...

Thanks a lot qxh7: good to see you back in the game!

9/14/2006 09:02:00 PM  
Blogger SamuraiPawn said...

Thank you for one of the most informative and interesting chessblogs on the net. Keep up the good work.


9/18/2006 04:04:00 AM  

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