Chapter 12 - Problem solving and expertise
Chapter Summary
Simulations of Key Experiments
Case Studies
Recording the eye movements of expert chess players
Background
Why are some people so very much better at chess than others? One possibility is that better players have more efficient cognitive processes, such as working memory or intelligence. However, the classic studies by De Groot (1946) on skilled performance showed that chess experts do not have superior general cognitive processes, but rather have very specialised cognitive strategies. For example, expert chess players have better recall than novices for board game configurations, but not for random configurations. In addition, in searching for a move, the chess master makes use of better-organised long-term memory than do novices. Previous research has also examined the eye movements of chess experts and it has been found they pay more attention to empty board spaces than novices, suggesting they pay greater attention to the relations between chess pieces (Holding, 1985; Reynolds, 1982).
However, the previous studies examined frame-by-frame film sequences to extract eye movement data and there is a question over the reliability of this method. Charness et al. (2001) studied the eye movements of expert chess players and compared them with less skilled, intermediate chess players. The aim of the experiment was to identify whether experts looked at empty squares more and fixated more on more salient pieces than non-experts (a salient piece is a chess piece that has greater importance for the current position in the game).
Method
The researchers exploited new technology that enables a researcher to identify the precise location of an eye fixation on a computer screen every 4 ms. The system works by sending an infra-red beam to the cornea and measuring its reflection. Details of the reflection indicate the direction of the eye and hence the location can be calculated. In each trial, expert chess players and intermediate chess players were given a board configuration and were asked to identify the best move as quickly as possible. There were five trials in all. The data recorded included reaction time, whether the solution was the best or not and the eye fixation data.
Results
The results showed that, as predicted, experts were faster and more accurate at identifying the best solution than intermediates. The fixation data revealed that experts made larger amplitude saccades (spatially larger eye movements), produced many more fixations on empty squares and produced a greater proportion of fixations on salient pieces than did intermediates.
Interpretation
The results imply that experts show more efficient encoding of the problem than do intermediates. This leads to “rapid recognition of salient relations among distant pieces, thereby enabling the player to focus on appropriate parts of the board. These processes set the stage for the generation of plausible moves that enable swifter and more accurate problem solving” (Charness et al., 2001, p. 1150). The finding that fixation on salient pieces occurs within the first 2 seconds supports the interpretation that experts also make greater use of peripheral vision than do intermediates. The findings are consistent with the view that perceptual skill gives an important advantage in chess. They also support the position of De Groot (1946/1978) that “one of the keys to skill in chess lies not in the thought processes that constitute search through the tree of move possibilities, but rather in the initial encoding of the relationships among the pieces in a chess position” (p. 1151).
Conclusion
The method used in this study allowed the researchers to identify that, for chess playing, important perceptual advantages, such as perceiving the relationships between the important pieces in a game, occur within the first few seconds.
References
Charness, N., Reingold, E.M., Pomplun, M. & Stampe, D.M. (2001). The perceptual aspect of skilled performance inches: Evidence from eye movements. Memory & Cognition, 29(8): 1146–52.
De Groot, A.D. (1946). Het denken van den schaker. Een experimenteel-psychologische studie. Amsterdam: Noord-Hollandsche Uitgeversmaatschappij.
De Groot, A.D. (1978). Thought and choice in chess (2nd edn). The Hague: Mouton.
Holding, D.H. (1985). The psychology of chess skill. Hillsdale, NJ: Lawrence Erlbaum Associates.
Reynolds, R.I. (1982). Search heuristics of chess players of different calibres. American Journal of Psychology, 95: 383–92 [doi: 10.2307/1422131].