Mapping the outer reaches of the learning curve: Complex intellectual skill performance after decades of extensive practice.

Little is known about the outer reaches of learning curves for very complex cognitive skills exercised over decades. Can skill performance improve as long as practice lasts or do all learners ultimately plateau? Furthermore, does natural talent set widely varying performance limits or do all learning curves eventually converge? Chess skill learning curves were examined for 333 players, mostly grandmasters, who, over a median 20 years, played at least 1500 internationally-rated games. Curves of nine of the 333 participants who played more than 3050 games, and one of the 333 and two others who played more than 4250 games over more than 30 years, also were examined.

Learning curves in highly skilled chess players: a test of the generality of the power law of practice.

The power law of practice holds that a power function best interrelates skill performance and amount of practice. However, the law's validity and generality are moot. Some researchers argue that it is an artifact of averaging individual exponential curves while others question whether the law generalizes to complex skills and to performance measures other than response time.

Gender differences in intellectual performance persist at the limits of individual capabilities.

Males predominate at the top in chess, and chess is a useful domain to investigate possible causes of gender differences in high achievement. Opportunity, interest and extent of practice can be controlled for. Organized chess has objective performance measures, extensive longitudinal population-level data and little gatekeeper influence.

Practice other than playing games apparently has only a modest role in the development of chess expertise.

Evidence that chess expertise rests on practice alone mostly comes from studies using a correlational retrospective recall paradigm, which confounds amount of study with number of games played and possible innate talent. Researchers also often use latest performance rating and include participants who play and study little. Study 1 partially replicated such studies with improvements such as use of peak rating and a large, skilled sample.

Testing the accuracy of the retrospective recall method used in expertise research.

Expertise typically develops slowly over years, and controlled experiments to study its development may be impractical. Researchers often use a correlational, retrospective recall method in which participants recall career data, sometimes over many years before. However, recall accuracy is uncertain.

Individual differences in expertise development over decades in a complex intellectual domain.

Learners acquire expertise at different rates and reach different peak performance levels. Key questions arise regarding what patterns of individual differences in expertise development occur and whether innate talent affects such development. International chess is a good test domain for both issues, because it has objective performance measures, actual practice measures (number of games), longitudinal population data, and minimal gatekeeper influence.

A complete database of international chess players and chess performance ratings for varied longitudinal studies.

Chess is an oft-used study domain in psychology and artificial intelligence because it is well defined, its performance rating systems allow ea sy identification o f experts and their development, andchess playing is a complex intellectual task However, usable computerized chess data have been very limited. The present article has two aims. The first is to highlight the methodological value of chess data and how researchers can use them to address questions in quite different areas.

IQ, visuospatial ability and the gender divide: a reply to Bilalić and Mcleod.

Bilalic and McLeod's arguments fall short on several grounds. There are excellent logical reasons to expect strong ability/chess expertise links and specific research evidence to date is sparse, with mixed findings. Data are presented from Georgia, which has a high female participation rate in chess, which suggest that differing gender motivation levels and participation rates impact relatively little on chess performance differences at the extreme.

Are gender differences in high achievement disappearing? A test in one intellectual domain.

Males traditionally predominate at upper achievement levels. One general view holds that this is due only to various social factors such as the 'glass ceiling' and lack of female role models. Another view holds that it occurs partly because of innate ability differences, with more males being at upper ability levels.