Why do some people learn complex skills with apparent ease, and ultimately reach expert levels of performance, while others struggle to move beyond a novice level? What distinguishes novices from experts in music, science, sports, and professions? Over a century ago, Sir Francis Galton, the founder of the scientific study of individual differences in psychological traits, argued that "genius" is hereditary -- that greatness is born, and that a person's environment has little to do with success in life. Galton was wrong. To a very large degree, expert-level performance reflects knowledge and skills that can only be acquired through experience. The Florida State University psychologist K. Anders Ericsson and his colleagues asked violinists at an elite music academy in Germany to estimate the amount of time they had devoted to deliberate practice for each year since they started playing violin. By the age of 20, the best players had accumulated an average of over 10,000 hours -- thousands of hours more than less accomplished groups.
Summarizing Ericsson's research in his bestseller Outliers, Malcolm Gladwell described 10,000 hours as the "magic number" of expertise. But recent research shows that some people require much more deliberate practice than others to become experts. The best evidence for this comes from a study of chess players by the cognitive psychologists Fernand Gobet and Guillermo Campitelli. Gobet and Campitelli found that some chess players needed literally thousands of hours more deliberate practice than others to reach "master" status, a very high level of expertise. It took one player just 3,000 hours, but another over 20,000 hours. There is no magic number of expertise.
This and similar evidence for wide ranges of deliberate practice among experts suggests that factors other than deliberate practice are critical for becoming an expert. But what are these other factors? Part of the answer is general intelligence -- the psychological trait that a person's IQ score reflects. Elizabeth Meinz and I had pianists perform a "sight-reading" task in which they played pieces of music with no preparation. We also had the pianists estimate how much deliberate practice they had accumulated, and perform tests of working memory capacity. Working memory capacity is the ability to hold in mind information over a short period of time that many cognitive psychologists think of as a core component of general intelligence. We found that deliberate practice accounted for nearly half of the performance differences across the pianists in the sight-reading task -- a massive contribution by statistical standards. But working memory capacity predicted performance differences, as well. Regardless of amount of deliberate practice, the pianists with a high level of working memory capacity tended to perform better than others on the sight-reading task.
Further evidence for the importance of general intelligence comes from a study by Vanderbilt University researchers David Lubinski and Camilla Benbow. They found that individual differences in general intelligence in childhood predicted individual differences in scientific achievement in adulthood. For example, compared to people who "only" scored in the 99.1 percentile, those who scored in the 99.9 percentile -- the profoundly gifted -- were about three times more likely to earn a Ph.D. in a science, math, or engineering field. Does this necessarily mean that it is impossible for a person with an average, or even below average, IQ to earn a Ph.D. in one of these fields? It does not. Does it mean that it is unlikely, relative to a person with a high IQ? It does. This is bad news if you buy into the egalitarian view that most anyone can achieve most anything with enough hard work -- especially since individual differences in IQ are not only influenced by genetic factors, but are also highly stable across the lifespan. But there's a silver lining: If you have an accurate idea of your abilities (or "talents"), and of the likelihood of achieving one goal vs. some other goal given these abilities -- say earning a Ph.D. in electrical engineering vs. becoming a master electrician -- you can make an informed decision about which goal you want to devote your time, money, and energy to pursuing.
What does all of this say about whether experts are born are made? The answer is "both." Experts are born because people come into the world differing in ways that turn out to matter for real-world achievement. But experts are made because there is no getting around the necessity of a long period of practice and training for reaching a high level of performance. This is my take. Take it for what it's worth.