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.