Cognitive and Neuropsychological Mechanisms of Expertise: Studies with Chess Masters

Research on expertise in visual-spatial tasks such as chess has ignored the introspective reports of top-level practitioners, overemphasized pattern recognition as the sole mechanism underlying skilled performance, and neglected the role of mental imagery in the thinking process. In addressing these limitations I propose a new theory of expertise, the “mental cartoons hypothesis,” and illustrate its properties by application to chess, which has historically been the primary domain for psychological studies of human expertise. Experiment 1 uses a classic image-scanning paradigm to show that chess masters and novices differ substantially in their ability to visualize chess moves, even in semantically impoverished contexts, extending the range of novice-expert differences from pattern recognition and knowledge representation to mental imagery processing. Experiments 2 and 3 exploit original very-long-term memory recognition and recall tasks to show that the memory representations of famous chess positions held by chess masters include both pattern and conceptual information, supporting a key distinction between this theory and its predecessors. Experiment 4 uses computer analysis of 1188 chess games between grandmasters to show that when players have additional time to think ahead, the quality of their decisions improves significantly, refuting a claim extrapolated from theories that emphasize fast pattern recognition over slow search processes. Experiments 5 and 6 investigate hemispheric specialization for chess perception, an issue not addressed by previous theories, and find that chess masters have a righthemisphere advantage for recognizing previously studied normal chess positions and for Psychological Mechanisms of Expertise in Chess / 4 parsing normal chess positions into component patterns. This is consistent with other neuropsychological evidence that ties the right hemisphere to chess skill. I also discuss more specific brain mechanisms that may support chess expertise, compare the mental cartoons hypothesis to other theories, suggest several specific experiments and general directions for future research, and argue that the study of expertise is relevant to a broad range of issues in human cognition. Psychological Mechanisms of Expertise in Chess / 5