Saturday, December 27, 2014

Expertise – a matter of practice? Part B


Deliberate practice: Is that all it takes to become an expert? 
David Z. Hambrick ,  Frederick L. Oswald , Erik M. Altmann , Elizabeth J. Meinz, Fernand Gobet , Guillermo Campitelli .  Intelligence 45 (2014) 34–45

In the previous post we've seen that practice explains about 34% of the variance in chess performance.  A significant amount,  but there certainly are other factors that explain the variance.  What are they?  And what about music?

The musicians who took part in the music studies discussed in this paper had different degrees of expertise.  They stated their formal music education   and estimated the number of hours they practiced each week throughout the years.

The performance criterion was expert ratings of the player's performance, the number of errors made by pianists while accompanying, pianist's ability to sight read the score and other similar measures.

As in chess, music practice explained 30% of the variance in music performance.  In one of the chess studies, a certain chess player needed 26 years of practice to attain master level, while another player attained master level in less than 2 years.  Likewise in music: at each skill level, some musicians needed a fifth of the mean practice time for that level, while others needed four times the mean practice time.

If practice explains only 30-34% of the variance in performance in chess and music – what else explains it?

An early start – chess players who began at an early age became more successful, regardless of the amount of practice they had.  Simonton discovered, that the most successful and acclaimed classical composers began studying and composing music at an earlier age than less successful classical composers.  There may be a critical period for acquiring certain skills.

Intelligence – performance level in music and chess is significantly correlated with IQ. Of the cognitive abilities, working memory capacity accounts for the most significant amount of variance in performance.  The study tells of a six year old boy who was a piano prodigy, played in concerts and almost never practiced.  His working memory score in the Stanford Binet test was 158.

Genetics also predicts performance level.

Personality – especially grit – predicts high level performance in many areas.  Grit leads to an ability to invest in hours of hard practice, to overcome difficulties etc.  I guess that other personality factors like interpersonal ability, self consciousness and openness to experience are also relevant, as well as other factors that I haven't mentioned. 

One can argue, that since this study is based on player's estimations of the amount of practice they had had years ago, the data is not so reliable.  But the authors claim that retrospective reports have reasonably good correlations with diary based reports. 

Another reason for my tendency to believe these claims is the fact that IQ scores are correlated 0.4-0.7 with school grades.  This is a kind of a "mirror image" of the study we are discussing.  0.4-0.7 correlations are quite significant, but obviously other factors also influence success in school.  There's no doubt that student's motivation and grit matter, and also teaching quality, school climate, the home environment and other factors.


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