Keep practicing, and you might become an expert. Or maybe you won't. Who knows? Not the experts, suggests a raging debate. 
 
 Made famous by Outliers: The Story of Success, by Malcolm Gladwell, the 2008 book's "10,000-hour rule"—the number of hours of practice needed to acquire mastery of a skill—looks increasingly beleaguered. 
 
 Underlying arguments over whether winners are made or born, or over nature versus nurture, the disagreement points to deep uncertainty about who should receive expert instruction and how best to teach people to excel. 
 
 "No one disputes that practice is important," says psychologist David Zachary Hambrick of Michigan State University in East Lansing. "Through practice, people get better. The question is whether that is all there is to it." 
 
 Kicking off the fracas, a study published last May in the journal Intelligence by Hambrick and colleagues suggested that practice explains only about a third of success among musician and chess masters. A series of responses to the study have since appeared in the journal, which is generally seen as a bastion of researchers who argue over the meaning of I.Q. scores. 
 
 The debate climaxed last month in the journal with the original study's authors' reply to a reply from psychologist K. Anders Ericsson of Florida State University in Tallahassee. Ericsson is best known for the research on premiere violinists touted in Gladwell's book, which credited the rule to Ericsson and other previous research efforts. 
 
 For his part, Gladwell participated in an MIT Sloan Sports Analytics Conference debate in early March with writer David Epstein, author of The Sports Gene: Inside the Science of Extraordinary Athletic Performance (which, not surprisingly, looks at the genetic links to winning in sports). The debate was the latest skirmish in a long-running fight over the amount of practice needed in sports and other endeavors. 
 
 Gladwell summed up the idea behind his deliberate practice rule as, given enough motivation, "if you are smart enough to get through college, you can be a good cardiac surgeon." 
 
 Fiddling Around 
 
 In last year's Intelligence study, Hambrick's team looked again at case studies of master musicians and chess players, the subjects of Ericsson's research. After quizzing the players on their lifetime hours of deliberate practice (as opposed to performances or play), they concluded that practice accounted for only 30 percent of success in music and 34 percent in chess. 
 
 They also found wide variability in the hours of practice. Chess grand masters had put in from 832 to 24,284 hours of work, although the average was around 10,530 hours. Musicians' efforts ranged from 10,000 to 30,000 hours. 
 
 The variability in hours of practice washes away any meaning from the 10,000-hour rule, Hambrick suggests. 
 
 In his response, Ericsson says that this kind of critique inappropriately mixes data about less-skilled folks into the analysis. (He also notes that he wrote about this kind of variability in practice in a 2013 British Journal of Sports Medicine editorial: "There is nothing magical about 10,000 hours.") 
 
 Hambrick counters that Ericsson's reliance on only a few supreme performers for his studies of expertise turns the studies into anecdotes. "If we don't have enough data points in the study to say anything statistically, then it isn't science." 
 
 To some extent, says psychologist Phillip Ackerman of Georgia Tech in Atlanta, expertise studies are butting up against the limitations of social science research, where the study variables—human beings—are more squirrelly than are the uniformly behaving atomic particles or molecules of the physical sciences. 
 
 "I think what all this shows is the limitations of case studies to say things about human beings," says Ackerman, who contributed one of the recent commentaries to Intelligence. "To a certain extent what we have here is people talking past each other." 
 
 Battle of the Straw Men 
 
 Haunting the 10,000-hour rule argument are the specters of two influential, but discredited, scientists. 
 
 The first, Francis Galton, the 19th-century father of eugenics, argued that heredity essentially explained all talent and expertise. Galton's racist ideas inspired the Nazi's horrific notions of racial purity. 
 
 The second, John Watson, the early-20th-century father of behaviorism, argued, 
 
 "Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors." 
 
 To his credit, Watson acknowledged he was "going beyond the facts" in this contention. But his 1920s advice on child-rearing led some to treat their children with emotional detachment, which was terrible advice for parents. 
 
 Today's 10,000-hour rule debate is often pitched as a fight over which of these extremes, nature or nurture, is more important when it comes to acquiring expertise. And the participants in the debate often paint their opponents as taking an extreme view of how expertise is acquired. 
 
 Gladwell, for example, said at the MIT debate that Ericsson is guilty of "expanding and stretching" the 10,000-hour rule toward being an absolute, far from his own view of it as more of a principle for people prescreened for aptitude for a skill. (Last year, he wrote in The New Yorker that complaints about his book "makes me think that there is another Malcolm Gladwell out there, with far more eccentric views than mine.") 
 
 Ericsson notes that Gladwell's book mistakes the average of 10,000 hours that experts took to master a skill described in his research with the total they required. "In fact, by the age of twenty, the elite performers had each totaled 10,000 hours of practice," says Gladwell in Outliers. 
 
 Aside from obvious genes for height or body size that help people in sports such as basketball, Ericsson says his real position is simply that he doesn't see evidence for genes that help people acquire expert levels of performance, as Epstein's book on elite athletes describes. 
 
 "The genes might well be there, but until we definitely identify them, I think we can't go beyond that," Ericsson says. In the era of the human genome, he argues against a stampede toward genetic explanations for things. 
 
 Hambrick and other 10,000-hour critics see this as "moving the goalposts" in a scientific debate, backpedaling from an earlier strong position to a weaker one while refusing to concede. 
 
 Plenty of studies suggest that aside from practice hours, individual differences help explain success, Georgia Tech's Ackerman says in Intelligence. Such differences range from socioeconomics to coaching to I.Q. 
 
 A Psychology of Sport and Exercise journal study out on March 3, for example, found no difference between the number of hours practiced among kids who grew up to be professional soccer players and kids who didn't. 
 
 The big difference between them was the amount of good coaching they received at a young age. 
 
 Think of the Children 
 
 The participants in the disagreement often voice two opposing concerns. 
 
 One fear Ericsson expresses is that if talent is viewed as somehow innate and not the result of practice, disadvantaged kids will be cut off from opportunities in education and sports. 
 
 "Nobody is going to be able to fly," Ericsson says. "But some kids are going to be blown away by the number of things they can do if they're given the chance." 
 
 On the other hand, Ackerman worries that telling people they just need to practice more might set them up for failure: "The odds are pretty good, but not impossible, that if you have an I.Q. of 70, you're probably not going to get a Ph.D. in particle physics." 
 
 Practice, then, is just one more ingredient in success. "There aren't innate abilities. Aside from our reflexes, everything is learned in one way or the other," Ackerman says. "Motivation, timing, and luck are all in there too." 
 
 Correction: The original story incorrectly attributed author David Epstein's first name. ||||| Flickr/FaceMePLS 
 
 As a teenager in Sweden, Anders Ericsson used to play chess against one of his classmates, a boy considerably worse at the game than Ericsson. Every time they'd play, Ericsson would trounce him. 
 
 Then one day, the classmate beat him. 
 
 Ericsson wanted to know: What exactly had the boy done to improve his performance so drastically? 
 
 Though Ericsson didn't realize it then, the question would come to define his life's work. 
 
 Advertisement 
 
 In the years that followed his defeat at the hands of his classmate, Ericsson found himself less interested in improving at chess and more interested in learning how people improve at anything. 
 
 Today, Ericsson is a professor of psychology at Florida State University, where he specializes, among many topics, in the science of peak performance. He is, in other words, an expert on experts. 
 
 Anders Ericsson. Anders Ericsson According to Ericsson's research and logic, the sole reason you aren't a virtuoso violinist, or an Olympic athlete, or another kind of world-class performer, is that you haven't engaged in a process he calls "deliberate practice." 
 
 In general, according to Ericsson, deliberate practice involves stepping outside your comfort zone and trying activities beyond your current abilities. While repeating a skill you've already mastered might be satisfying, it's not enough to help you get better. Moreover, simply wanting to improve isn't enough — people also need well-defined goals and the help of a teacher who makes a plan for achieving them. 
 
 At first, the teacher gives feedback on your efforts; eventually, you can spot problems in your own performance and tweak it accordingly. Ericsson's research has led him to study expert spellers, elite athletes, and memory champions — and he attributes their diverse successes to deliberate practice. 
 
 Most notably, Ericsson's work on deliberate practice formed the basis for the "10,000-hour rule" featured in Malcolm Gladwell's book, "Outliers": Put in about 10,000 hours of practice, and you'll become an expert. 
 
 Unfortunately, Ericsson says Gladwell misinterpreted his research and that 10,000 hours of merely repeating the same activity over and over again is not sufficient to catapult someone to the top of their field. 
 
 Gladwell likely drew his conclusions from a paper that Ericsson and his colleagues published in 1993, which studied 40 violinists in Germany. Specifically, the researchers focused on what factors differentiated the best musicians from the good or the mediocre ones. 
 
 After asking all the violinists to give detailed records of how they spent their time, on music practice as well as on other activities, the researchers found that the top two groups of violinists spent significantly more hours practicing alone than the others did. The researchers also studied pianists and yielded similar conclusions. 
 
 Advertisement 
 
 On average — and Gladwell likely drew his conclusion from this — the best violinists had spent a total of 10,000 hours practicing their craft by 20 years old. Some, however, had practiced much more, or less, than that. (Gladwell's publicist didn't respond to a request for comment.) 
 
 Ericsson's findings from the past three decades suggest that deliberate practice is the key to achieving high levels of performance in any field. 
 
 In his book, "Peak: Secrets From the New Science of Expertise," cowritten with the journalist Robert Pool, Ericsson translates the principles of deliberate practice from academic-speak into plain language. 
 
 When I spoke with Ericsson by phone in May, he told me that people who think practice can only get you so far aren't talking about the same kind of practice as he is. 
 
 Advertisement 
 
 As for whether genetic differences — say, in cognitive or physical ability — account for variations in achievement, Ericsson is skeptical. 
 
 Height and body size, he said, are the only genetically predetermined traits that can't be altered much through practice and have a meaningful impact on performance. 
 
 Even intelligence, Ericsson said, is not directly linked to expert performance. In "Peak," he cites a study by British researchers, which found that intelligence does indeed predict chess skill among children. But when those researchers looked only at kids who were elite chess players, a higher IQ was, in fact, linked to worse skills. 
 
 Kids with high IQs learn how to play chess faster — but once their peers catch up, they may no longer have an advantage. Tim Vizer/AP While a high IQ helps kids learn the game and acquire the basic skills required to play, once other kids catch up intelligence level probably doesn't matter, Ericsson explains. But deliberate practice does. 
 
 "I've been spending now 30 years trying to look for kind of limits that would actually constrain some individuals from being successful in some domain," Ericsson told me. "And I'm surprised that I've yet really to find such limits." 
 
 In the last few years, however, Ericsson's findings on deliberate practice have come under intense scrutiny from other psychologists. 
 
 Research published in May 2016 analyzed the results of thousands of studies and found that while deliberate practice did indeed account for some of the differences between more and less skilled athletes, it couldn't account for all of them. The researchers can't say for sure what other factors matter, but they propose that genetically influenced physical traits such as how easily you build muscle mass, and even psychological traits like confidence, play a role. 
 
 Prior, in 2014, researchers analyzed six studies of chess players and eight studies of musicians and found that deliberate practice was not the only explanation for high performance in either domain. Instead, other factors, like intelligence, might be at play there as well. 
 
 In a response to the 2016 paper, published in the same journal, Ericsson wrote that these conclusions are inaccurate, largely because they conflate total hours of accumulate practice with deliberate practice specifically. 
 
 Unless you're performing exercises that were assigned by a teacher to help you improve in a particular area, Ericsson believes you're not engaging in deliberate practice. Plenty of practice activities are completely ineffective and won't lead to improvement, he told me when we spoke again in June. 
 
 Given the right practice conditions, could I really become an exceptional writer? Wikimedia Reading over the scientific studies on deliberate practice, I couldn't help but wonder what these findings mean for professional writers. 
 
 Given the right practice conditions, could I really become the next Tom Wolfe or Michael Lewis? 
 
 Based on my understanding of Ericsson's research, it would take a lifetime of adherence to rigid practice criteria — but yes, it would theoretically be possible. 
 
 I posed a similar question to D. Zachary Hambrick, a professor of psychology at Michigan State University who coauthored both the 2014 and 2016 papers debunking Ericsson's findings. 
 
 Hambrick said he didn't know. To date, no research has explored the role of deliberate practice in writing expertise. But Hambrick also said he'd be surprised if writing ability was entirely dependent on deliberate practice. In other words, unless I started out with certain requisite abilities, a lifetime might not be enough for me to achieve Wolfe or Lewis levels. 
 
 Hambrick, however, kept reiterating that practice is important, if not essential, to the development of expertise in any field. 
 
 "I don't think there's any downside to believing in the power of practice," he said. "I do think there is a possible downside to sort of thinking that anybody can accomplish anything with no limits." 
 
 Advertisement 
 
 To put it frankly, believing that people can deliberately practice their way to peak performance might be a waste of time. 
 
 "People might start training in things and end up not improving much when they could have invested their resources and energies and time and training in other things which they might be more likely to excel at," Hambrick said. 
 
 Beyond the controversy over whether deliberate practice leads directly to expertise, perhaps the insight that struck me most in "Peak" was this: To become an expert, you may need to be willing to sacrifice short-term pleasure for potential satisfaction of success down the road. A key tenet of deliberate practice is that it's generally not enjoyable. 
 
 Instead, it's about doing things that don't come naturally or easily, which can be tough. "Practice really involves failing a lot until you eventually reach your goal," Ericsson told me. 
 
 Elite skaters spent more time practicing jumps and spins. REUTERS/Lucy Nicholson He cited research on figure skaters (which appeared in this book) that found elite skaters spent more time than average ones practicing jumps and spins in routines they hadn't yet mastered. By contrast, average skaters spent more time going over routines they were already good at. 
 
 So what's the downside to becoming an expert? Perhaps it's that you need to devote yourself wholly to one area — that while one door flies wide open, others slowly creak to a close. Ericsson told me he doesn't know of anyone who's become a world-class expert in more than one skill. 
 
 That's why, he said, becoming an expert in anything and placing 100% focus on becoming the best in one domain "may not be basically the right thing here for even the majority of people." 
 
 That is to say, there's nothing inherently wrong with being average. In fact, working toward expertise in any area can be a grueling, lonely, and often ugly undertaking. 
 
 Ericsson, however, does practice what he preaches. He said he personally uses the principles of deliberate practice to become a better researcher. Every article he published, as a postdoctoral researcher and afterward, was the result of multiple drafts and feedback from the psychologists he was working with. 
 
 Ericsson cited one 1980 paper, which he cowrote with the late cognitive psychologist Bill Chase and published in the journal Science. 
 
 "Partly because I am Swedish," Ericsson said, "it took over 30 different drafts with comments on problems and issues by Bill before we had an article that Bill was willing add his name to."
– If you were hoping to become a chess master by practicing 10,000 hours, think again. Contrary to the theory that expertise at chess is based on intensive training, researchers at the University of Michigan have concluded based on a meta-analysis of 19 studies that hard work is important but not enough. In this game, if you're not smart, you're probably sunk. "When it comes to expertise, training and practice certainly are a piece of the puzzle," psychology professor Zach Hambrick says. "But this study shows that, for chess at least, intelligence is another piece of the puzzle." The researchers found that intelligence is always linked to chess skill no matter the age of the participant, though the link appears strongest in younger players or those at lower skill levels. It's possible, the team suggests, that this is because upper-echelon players are all pretty bright anyway—at that point, "They're all smart cookies," as the Huffington Post puts it. In an interview with Business Insider earlier this summer, Hambrick conceded that practice is probably important for mastery in any field, but he cautions against "thinking that anybody can accomplish anything with no limits" based solely on hard work. (The youngest ever chess grandmaster in the US has been playing since he was 5.)