When experts exhibit their superior performance in public their behavior looks so effortless and natural that we are tempted to attribute it to special talents. [...] The critical difference between expert musicians differing in the level of attained solo performance concerned the amounts of time they had spent in solitary practice during their music development, which totaled around 10,000 hours by age 20 for the best experts, around 5,000 hours for the least accomplished expert musicians and only 2,000 hours for serious amateur pianists.
