Location coding in chess

Whether the chunks used in memorizing chess positions are general and relatively encoded schemata or very precisely coded instances is a problem that has raised some controversy within the psychology of chess skill. As chess research has had a strong impact on expertise research, this problem is important in many areas of skills research other than chess. To resolve it, four experiments were set up. In the experiments it was shown that subjects were better at recalling correctly located non-transposed chunks than transposed chunks, which were similar in structure but incorrectly located on the chessboard. The results imply that the representation of chess-specific patterns in the memory of a chess player contains not only information about the forms of chess-specific patterns, but also about their absolute locations on the chessboard. This provides an explanation for the well-known interaction between skill and type of position and its disappearance in recent experiments by Lories and Saariluoma. It can be argued that the difficulty of recalling random positions is not chiefly caused by the total absence of chunks but by their dislocation.     

Mechanisms and neural basis of object and pattern recognition: a study with chess experts

Comparing experts with novices offers unique insights into the functioning of cognition, based on the maximization of individual differences. Here we used this expertise approach to disentangle the mechanisms and neural basis behind two processes that contribute to everyday expertise: object and pattern recognition. We compared chess experts and novices performing chess-related and -unrelated (visual) search tasks. As expected, the superiority of experts was limited to the chess-specific task, as there were no differences in a control task that used the same chess stimuli but did not require chess-specific recognition. The analysis of eye movements showed that experts immediately and exclusively focused on the relevant aspects in the chess task, whereas novices also examined irrelevant aspects. With random chess positions, when pattern knowledge could not be used to guide perception, experts nevertheless maintained an advantage. Experts' superior domain-specific parafoveal vision, a consequence of their knowledge about individual domain-specific symbols, enabled improved object recognition. Functional magnetic resonance imaging corroborated this differentiation between object and pattern recognition and showed that chess-specific object recognition was accompanied by bilateral activation of the occipitotemporal junction, whereas chess-specific pattern recognition was related to bilateral activations in the middle part of the collateral sulci. Using the expertise approach together with carefully chosen controls and multiple dependent measures, we identified object and pattern recognition as two essential cognitive processes in expert visual cognition, which may also help to explain the mechanisms of everyday perception.     

Aspects of skilled imagery in blindfold chess

Blindfold chess is a very good task environment to study skill-based mental images or skilled imagery. Seven experiments providing information on different aspects of skilled imagery in blindfold chess were made. In all experiments very clear skill-related differences in the operation of chess-specific materials could be found. It will also be argued that chess-specific patterns or chunks are important in skilled subjects' construction of images and the operation of these images relies on the cooperation of visual working memory and long-term memory.     

Recall memory for visually presented chess positions

A series of three experiments replicated and extended earlier research reported by Chase and Simon (1973), de Groot (1965), and Charness (Note 1). The first experiment demonstrated that the relationship between memory for chess positions and chess skill varies directly with the amount of chess-specific information in the stimulus display. The second experiment employed tachistoscopic displays to incrementally "build" tournament chess positions by meaningful or nonmeaningful chunks and demonstrated that meaningful piece groupings during presentation markedly enhance subsequent recall performance. The third experiment tested memory for one of two positions presented in immediate sequence and demonstrated that explanations based on a limited-capacity short-term memory (Chase & Simon, 1973) are not adequate for explaining performance on this memory task.     

Chess expertise in children

This paper reports several studies of chess expertise in children who play competitive chess. The first study examines (1) the relationship between experience and skill among 113 school-age children (grades 1 through 12); and (2) the relationship between chess skill and scores on various spatial and logical abilities tests among the top 15 players. Improvement in skill is related to experience, and chess players score higher than average on the Raven's Progressive Matrices. Also, scores on a chess-specific test, the Knight's Tour, correlate with scores on the Raven's. The second study reports three experiments with 59 Ss involving chess-specific tasks in memory, perception, and similarity judgements. The first two experiments replicated and extended Chase and Simon (1973). The third experiment, which asked Ss to judge similarities of chess positions, demonstrated that similarity judgements become more global and abstract with increased skill. The final section describes qualitatively how children's chess expertise compares to that of adults. Drawing upon Anderson (1985), we focus on some distinctive features of children's chess play and on some successful techniques in coaching young players.     

Chunk hierarchies and retrieval structures: Comments on Saariluoma and Laine

The empirical results of Saariluoma and Laine are discussed and their computer simulations are compared with CHREST, a computational model of perception, memory and learning in chess. Mathematical functions such as power functions and logarithmic functions account for Saariluoma and Laine's correlation heuristic and for CHREST very well. However, these functions fit human data well only with game positions, not with random positions. As CHREST, which learns using spatial proximity, accounts for the human data as well as Saariluoma and Laine's correlation heuristic, their conclusion that frequency-based heuristics match the data better than proximity-based heuristics is questioned. The idea of flat chunk organisation and its relation to retrieval structures is discussed. In the conclusion, emphasis is given to the need for detailed empirical data, including information about chunk structure and types of errors, for discriminating between various learning algorithms.     

Mental imagery and chunks: Empirical and computational findings

To investigate experts' imagery in chess, players were required to recall briefly presented positions in which pieces were placed on the intersections between squares (intersection positions). Position types ranged from game positions to positions in which both the piece distribution and the location were randomized. Simulations were run with the CHREST model (Gobet & Simon, 2000). The simulations assumed that pieces had to be centered back, one by one, to the middle of the squares in the mind's eye before chunks could be recognized. Consistent with CHREST's predictions, chess players (N = 36), ranging from weak amateurs to grandmasters, exhibited much poorer recall for intersection positions than for standard positions (pieces placed on the centers of the squares). For the intersection positions, the skill difference in recall was larger for game positions than for the randomized positions. The participants recalled bishops better than they recalled knights, suggesting that Stroop-like interference impairs recall of the latter. The data supported both the time parameter in CHREST for shifting pieces in the mind's eye (125 msec per piece) and the seriality assumption. In general, the study reinforces the plausibility of CHREST as a model of cognition.     

The role of attack and defense semantics in skilled players’ memory for chess positions

There is much evidence that chess skill is based on chunks in memory that represent parts of positions from previously encountered games. However, the content of these chunks is a matter for debate. According to one view, (1) the closer two pieces are to each other on a board (proximity), the more likely they are to be in the same chunk, and (2) skilled players encode the precise locations of pieces. An alternative view is that what information is encoded in a chess chunk is determined more by processing of the attack/defense relations during evaluation. In three experiments, participants evaluated positions and completed recognition tests. Experiment 1 supported the view that expert players make more use of attack/defense relations than of locations of pieces in a recognition test. Experiments 2 and 3 demonstrated that, for both long and short presentation times, expert players' recognition for a piece within a position was primed more by a piece related by attack or defense than by a piece merely proximal. These findings challenge theories of expertise for chess that assume a primary role for proximity and location in determining which pieces are grouped together in memory.     

The generality of the levels of processing hypothesis: An application to memory for chess positions

The generality of the levels of processing approach to memory was tested by using chess positions rather than words as stimuli. Experiment 1 compared recall following semantic orienting instructions (find the best move and determine which side has the advantage), formal orienting instructions (determine the number of pieces on light squares and the number of pieces on dark squares), and intentional learning instructions using 19 novice chess players as subjects. Formal orienting instructions produced poorer recall than did either semantic orienting or intentional learning instructions, which yielded similar levels of retention. These results were replicated in Experiment 2 with 16 tournament chess players. Chess rating correlated with recall .82 under semantic orienting instructions but only —.15 under formal orienting instructions. It was concluded that the levels of processing framework has applicability outside the area of verbal learning.     

Chess players' intake of task-relevant cues

Patterns of chess pieces are important for chess players in storing information in memory-recall tasks. It also may be assumed that these patterns play a central role in the perceptual coding of task-relevant cues. Two perceptual classification experiments were done to test this assumption. Chess-players' intake of task-relevant cues was studied by measuring the reaction times of subjects in counting the minor pieces on the chessboard or searching for checks in the game and in random positions. Surprisingly, there was no interaction between the level of skill and the type of position. In Experiment 3, both a perceptual classification task and a memory-recall task using the same positions were presented to a group of chess players at the same session. In the perceptual classification task, there was no interaction between the level of skill and the type of position, but in the recall task there was strong interaction. The result suggests that the information intake of chess players, in its lowest levels, is not dependent on the learned patterns. The role of the patterns becomes important in defining the information to be looked for, but the patterns are not important in the early-stage perceptual structuring of a position.     

Recall or evaluation of chess positions as determinants of chess skill

Previous research has found that the ability to recall briefly presented chess positions varies with playing strength, except when random positions are used. The suggestion therefore arises that mastery consists of recognizing configurations that are associated with plausible moves. This approach is tested by comparing the memory scores and move-choice protocols of players in six skill categories, using random chess positions. Contrary to any strong form of recognition-association hypothesis, differences in chess skill are shown to persist although memory differences are abolished. It is further shown that the moves selected are not based on those few pieces that are remembered. Skill-related differences in the accuracy of positional evaluations also occur, but they are less marked than in earlier results. An alternative approach to chess skill seems appropriate, in which memory effects may function at the evaluation phase.     

Visual span in expert chess players: evidence from eye movements

The reported research extends classic findings that after briefly viewing structured, but not random, chess positions, chess masters reproduce these positions much more accurately than less-skilled players. Using a combination of the gaze-contingent window paradigm and the change blindness flicker paradigm, we documented dramatically larger visual spans for experts while processing structured, but not random, chess positions. In addition, in a check-detection task, a minimized 3 × 3 chessboard containing a King and potentially checking pieces was displayed. In this task, experts made fewer fixations per trial than less-skilled players, and had a greater proportion of fixations between individual pieces, rather than on pieces. Our results provide strong evidence for a perceptual encoding advantage for experts attributable to chess experience, rather than to a general perceptual or memory superiority.     

Understanding Our Understanding of Strategic Scenarios: What Role Do Chunks Play?

There is a crucial debate concerning the nature of chess chunks: One current possibility states that chunks are built by encoding particular combinations of pieces-on-squares (POSs), and that chunks are formed mostly by "close" pieces (in a "Euclidean" sense). A complementary hypothesis is that chunks are encoded by abstract, semantic information. This article extends recent experiments and shows that chess players are able to perceive strong similarity between very different positions if the pieces retain the same abstract roles in both of them. This casts doubt on the idea that POS information is the key information encoded in chess chunks, and this article proposes, instead, that the key encoding involves the abstract roles that pieces (and sets of pieces) play-a theoretical standpoint in line with the research program in semantics that places analogy at the core of cognition.     

Chess knowledge predicts chess memory even after controlling for chess experience: Evidence for the role of high-level processes

The expertise effect in memory for chess positions is one of the most robust effects in cognitive psychology. One explanation of this effect is that chess recall is based on the recognition of familiar patterns and that experts have learned more and larger patterns. Template theory and its instantiation as a computational model are based on this explanation. An alternative explanation is that the expertise effect is due, in part, to stronger players having better and more conceptual knowledge, with this knowledge facilitating memory performance. Our literature review supports the latter view. In our experiment, a sample of 79 chess players were given a test of memory for chess positions, a test of declarative chess knowledge, a test of fluid intelligence, and a questionnaire concerning the amount of time they had played nontournament chess and the amount of time they had studied chess. We determined the numbers of tournament games the players had played from chess databases. Chess knowledge correlated .67 with chess memory and accounted for 16% of the variance after controlling for chess experience. Fluid intelligence accounted for an additional 13% of the variance. These results support the conclusion that both high-level conceptual processing and low-level recognition of familiar patterns play important roles in memory for chess positions.     

The perceptual aspect of skilled performance in chess: Evidence from eye movements

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.     

Visuospatial representations used by chess experts: A preliminary study

Blindfold chess is played without the players seeing either the pieces or the board. It is a skill‐related activity, and only very skilled players can construct the mental images required. This is why blindfold chess provides a good task with which to investigate the spatial memory and skilled mental images of expert players. In a PET investigation, we compared memory performance and problem solving in very experienced chess players with their performance in an attention task, in which the subjects classified the names of chess pieces. The memory task predominantly activated the temporal areas, whereas problem solving activated several frontal areas. The relevance of these findings to concepts such as general imagery, skilled imagery, apperception, and long‐term working memory are discussed.     

中国象棋经验棋手与新手的知觉差异:来自眼动的证据

为探讨中国象棋领域内的专长效应及象棋专长的知觉编码优势,研究采用中国象棋棋局为实验材料,对比了经验棋手和新手在观看象棋棋局时视觉搜索、变化觉察和对棋盘的记忆。实验1呈现真实棋局和随机棋局,要求被试观看5秒后复盘,结果发现经验棋手的复盘正确率高于新手;经验棋手注视棋盘的眼跳幅度和瞳孔直径更大;经验棋手更多注视棋子间而不是棋子本身。实验2采用移动窗口范式控制了观看棋盘时视野大小,结果发现经验棋手在副中央凹呈现时复盘正确率更高,而新手不受视野大小的影响。实验3采用闪烁范式要求棋手觉察变化的棋子,结果发现经验棋手的觉察速度和正确率都优于新手;而且经验棋手在报告变化前就利用中央凹和副中央凹注视到了变化的棋子。结论认为:中国象棋与国际象棋类似,也存在专长的知觉编码优势效应;经验棋手不仅对棋盘记忆更好,而且可以利用存贮的组块和长期练习经验选择性加工棋盘结构信息,利用副中央凹提取信息,具有更大的知觉广度。研究为象棋专家可以利用副中央凹加工棋盘及具有更强的知觉编码能力提供了直接的证据。     

Dynamic perception in chess

The present study examines the dynamic aspects of perceptual processes in expert chess players. This topic is approached in terms of the anticipation processes carried out by experienced players during the encoding of chess positions. The aim of the first experiment, which used a short-term comparison task, was to stress the role of anticipation, which allows expert players to focus their attention on the area of the studied position where they expect the likely standard move to occur. The second experiment used a long-term recognition task. The results showed that expert players made many false recognitions on the new positions that could be expected from the positions presented in the preliminary study phase. Taken together, the results of the two experiments highlight the anticipatory component of expert perception.     

Five Seconds or Sixty? Presentation Time in Expert Memory

For many years, the game of chess has provided an invaluable task environment for research on cognition, in particular on the differences between novices and experts and the learning that removes these differences, and upon the structure of human memory and its paramaters. The template theory presented by Gobet and Simon based on the EPAM theory offers precise predictions on cognitive processes during the presentation and recall of chess positions. This article describes the behavior of CHREST, a computer implementation of the template theory, in a memory task when the presentation time is varied from one second to sixty, on the recall of game and random positions, and compares the model to human data. Strong players are better than weak players in both types of positions, especially with long presentation times, but even after brief presentations. CHREST predicts the data, both qualitatively and quantitatively. Strong players' superiority with random positions is explained by the large number of chunks they hold in LTM. Their excellent recall with short presentation times is explained by templates, a special class of chunks. CHREST is compared to other theories of chess skill, which either cannot account for the superiority of Masters in random positions or predict too strong a performance of Masters in such positions.     

Dynamic perception in chess

The present study examines the dynamic aspects of perceptual processes in expert chess players. This topic is approached in terms of the anticipation processes carried out by experienced players during the encoding of chess positions. The aim of the first experiment, which used a short-term comparison task, was to stress the role of anticipation, which allows expert players to focus their attention on the area of the studied position where they expect the likely standard move to occur. The second experiment used a long-term recognition task. The results showed that expert players made many false recognitions on the new positions that could be expected from the positions presented in the preliminary study phase. Taken together, the results of the two experiments highlight the anticipatory component of expert perception.