More Big Round Numbers: Does 10,000 Practice Hours Really Make for Greatness?

In a recent blog essay (here) I advised thinking critically about big round numbers, including claims that the brain has 100 billion neurons, that we use 10 percent of our brains, and that 10 percent of people are gay. 

Regarding the latter claim, a recent Gallup survey asked 121,290 Americans about their sexual identity: “Do you, personally, identify as lesbian, gay, bisexual, or transgender?” “Yes,” answered 3.4 percent.  And when a new National Center for Health Statistics study asked 34,557 Americans about their sexual identity, all but 3.4 percent of those who answered indicated they were straight. The rest said they were gay or lesbian (1.6 percent), bisexual (0.7 percent), or “something else” (1.1 percent).

Questions have recently arisen about another of psychology’s big round numbers—the claim that 10,000 practice hours differentiates elite performers, such as top violinists, from average to excellent performers.  As the distinguished researcher, Anders Ericcson, observed from his study of musicians (here), “the critical difference [is] 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.”

Not so fast, say David Hambrick, Brooke Macnamara, and their colleagues (here and here). In sports, music, and chess performance, for example, people's practice time differences account for a third or less of their performance differences. Raw talent matters, too.

Perhaps both are right?  Are superstar achievers distinguished by their unique combination of both extraordinary natural talent and extraordinary daily discipline?