We’re all familiar with the 10,000 hour rule, which was made famous by Malcolm Gladwell in his 2010 bestseller Outliers: The Story of Success. In it, Gladwell makes the argument that 10,000 hours of practice is a critical number that separates the great from the truly extraordinary. One of the bodies of work Gladwell relied on to support his thesis were from research by Florida State University Psychology Professor K. Anders Ericsson, the granddaddy of research on how people developing expertise.
Ericsson studied violinists from the West Berlin Music Academy: the highest performing students did not differ significantly from average or low performing students by IQ, family background, or other factors. The only thing that separated top students who and those who would likely end up as music teachers was the total number of hours they had logged over their lifetime engaged in deliberate, focused, independent music practice.