…excellence at a complex task requires a critical, minimum level of practice – surfaces again and again in studies of expertise. In fact, researchers have settled on what they believe is a magic number for true expertise: 10,000 hours.

“In study after study, of composers, basketball players, fiction writers, ice-skaters, concert pianists, chess players, master criminals,” writes the neurologist Daniel Levitin, “this number comes up again and again. Ten thousand hours is equivalent to roughly three hours a day, or 20 hours a week, of practice over 10 years… No one has yet found a case in which true world-class expertise was accomplished in less time. It seems that it takes the brain this long to assimilate all that it needs to know to achieve true mastery.” (more)

Gladwell unpacks the mythology of genius and discovers something close to historical inevitability…