Dan McLaughlin reckons he’s sat down to compose the farewell post to the Dan Plan a hundred times. “I just don’t know what to write,” he says.

Sitting in his spartan home in Portland, Oregon, McLaughlin is self-effacing and soft-spoken. He recently launched an artisanal soft-drink venture. Discussing the Dan Plan is like reaching back into another life: Seven-plus years ago, aged 30 and unsure even of which hand to grip a golf club in, McLaughlin quit his job as a commercial photographer, took in lodgers to cover the mortgage, husbanded his savings for green fees, and set out to make the PGA Tour, home to the world’s elite golfers.

He created a catchily named blog to document his quest, and in short order the Dan Plan commanded magazines spreads and TV spots. Along the way, it drew an avid community of followers riveted by the spectacle of a regular Joe living out an everyman fantasy. No less captivated: a salon of leading figures from the science of learning and human performance.

What could you achieve if you committed to something completely, all-in, no excuses? How far could you go? For five years, McLaughlin cast everything else aside—career, money, even relationships—to put this to the test. But then his back gave out. He pushed himself to the limit and still came up short.

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McLaughlin had never aspired to be a pro golfer. Growing up in Georgia, opportunities to play abounded, but he found the game stuffy, rule-bound. Closing on 30, though, he felt like he’d skated over life’s surface. He’d switched colleges and jobs. He liked being a commercial photographer enough, but his ultimate sentiment was meh. He wanted to commit to something, anything.

The conversation that planted the seed for the Dan Plan took place in June 2009, as McLaughlin hacked around a golf course in Omaha, Nebraska, with his brother. “We [talked] about the idea of quitting everything to pursue something single-mindedly and whole-heartedly,” McLaughlin recounts. “Did you need talent or was it all about hard work?”

Such questions were in the air. Malcolm Gladwell’s Outliers, the book that popularized the idea that mastery in a given field takes at least 10,000 hours of practice, had just come out, as had Geoff Colvin’s Talent is Overrated and Daniel Coyle’s The Talent Code, both of which emphasized the role of dedicated practice (and discounted natural-born talent) in excellence.

McLaughlin hadn’t read these tomes. But friends pressed them on him, and the Dan Plan took shape. It would test how far practice could take you; and, taking a cue from Outliers, its time horizon would be 10,000 hours of practice. Golf fit neatly with this empirical goal. There were no barriers to entry—top golfers come in all shapes and sizes, no genetic assists for certain body types. And McLaughlin was a novice in it, a standing start against which he could measure his progress. To document this, he began the blog through which he’d soon become an evangelist for the sovereignty of hard work. “The idea of talent is [like] living in a society of kings and princes,” he says. “If you don’t limit yourself by this idea ... it’s more like a democracy where anyone who’s willing to work [can] succeed.”

The blog also held his feet to the fire. “If you make [something] public, it’s harder to stop.”

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Fishing for advice once the project was underway, McLaughlin emailed K. Anders Ericsson, the Florida State University psychologist whose study of violin and piano virtuosi Gladwell cited in Outliers. The two struck up a correspondence.

Ericsson was impressed. In particular, he was taken with McLaughlin’s commitment to systematic, “deliberate” practice—something he says Outliers glossed over by implying mastery is simply a matter of accumulating hours. “My feeling was, ‘wow, this is really exciting.’”

Enlisting a coach, McLaughlin collected data on his performance and sent it to Ericsson, who plotted his improvement. McLaughlin built his game from the hole out. For months, all he did was putt. Gradually, he moved farther from the flag, adding clubs. Eighteen months in, he played his first full round. At peak practice, he was putting in four hours on the practice green and driving range and playing 18 holes daily. He was stingy in tallying hours toward the 10,000 mark, only counting concentrated practice.

Barely over halfway through, he’d pared his handicap to an all-time low of 2.6—a mark achieved by fewer than 6 percent of golfers.

With just one person, the Dan Plan was strictly a case study; what McLaughlin found wouldn’t prove anything either way about talent or hard work. But for the academic observers like Ericsson, it offered the spectacle of an attempt to test an idea, founded on retrospective studies, in real time. Moreover, McLaughlin would evaluate whether the dividends of long-term intensive practice were operative for adults as well as hothoused kids.

As he progressed, McLaughlin found that many of our instincts turn out to be self-defeating. “People’s intuitions about practice are nowhere near optimal,” says Robert Bjork, a professor in cognitive psychology at the University of California, Los Angeles, whose research has demonstrated the effectiveness of introducing “deliberate difficulty” into practice—for instance, constant variety, “interleaving” between different skills and “spacing” study to force students to retrieve, and embed, new knowledge between sessions.

“You want to increase arousal so [the brain encodes] information at a deeper level,’” says Mark Guadagnoli, a professor of neuroscience and neurology at the University of Nevada, Las Vegas, School of Medicine. “It’s [like] using a laser to engrave something versus a ballpoint pen.”

With advice from Bjork, Ericsson, Guadagnoli, and others, McLaughlin incorporated these principles. But only after he’d burned months drilling single skills like putting—intuitively the best way to practice, but actually the least effective. An article in Time from 2013 described McLaughlin as “a lab rat in human form.” But, of course, he was all human. Whereas his prospective peers on the pro circuit were, in his words, “on TV making millions or in college,” McLaughlin felt isolated. When his complimentary membership at an upscale club with a roster of serious players lapsed, he joined a cheaper club where it was hard to maintain focus among the weekend warriors. And when he met a partner with kids, his grand endeavor seemed more like selfish indulgence—especially with the Dan Plan bringing in, at most, $250 a month in donations, McLaughlin says.

According to the PGA, for every one of the 245 spots on the PGA Tour, there are 326,000 active golfers worldwide. Bjork got a look at McLaughlin’s game in 2014. “I could watch him and think it was remarkable for someone who hadn’t played before,” Bjork recounts. “Or, I could look at him ... and say the whole idea of [making] the pro tour was unrealistic.”

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Bjork believes that the Dan Plan was popular because it resonated with the regret-tinged curiosity many people feel about the roads not taken in their lives. Even world-renowned cognitive scientists aren’t immune to such wistfulness, it turns out: Bjork ranked among Minnesota’s best junior golfers, and considered committing full-time to the sport after graduating from college. Fearing the Vietnam draft, he enrolled in grad school instead.

“It’s hard to regret,” Bjork says. But he still wonders how good he could have been. “Maybe everybody has a lurking [question],” he speculates. “What if I’d pursued being a musician, writer, or actor?”

It’s a minor rumination most people discard—just another road not taken. But not for McLaughlin. “It was unique for someone to stop their personal life to take on a challenge like this,” Bjork says.

McLaughlin stuck to his task for years, but 6,003 hours in, his back would no longer comply. “I couldn’t swing a club for six months,” he says. Today, he’s fine—as long as he doesn’t try to play golf every day. And the Dan Plan is a digital ruin, trailing off mid-stream amid the plaintive questions of diehard fans: “What’s the latest Dan?”

Ericsson, for one, wants closure. He dreams of a foundation that would fund multiple Dans to devote themselves to excellence in different domains, mapping their steps for others. “For people in middle age, that sense some have that they’ve lost their chance is sad. If Dan could document his path more [that would give others] a trajectory.” Ericsson compares it to climbing a mountain: “The first person gets stuck but, over time, people figure out how to get to the top.”

For his part, McLaughlin doesn’t consider the Dan Plan a failure. “If I say it was a failure then I guess I’m a failure,” he says. “I don’t feel like a failure.”

But the Dan Plan crystallizes the sheer number of variables, beyond deliberate practice, involved in attaining excellence in a field—not least, reliable access to effective instruction and the support system and motivation provided by a cohort of peers striving toward the same goal. McLaughlin struggled to find both of those. And what about psychological factors, even the role of negative emotion—gnawing insecurity, for example—as a driving force behind high achievement?

“It’s a domain that’s pretty complex and hard to understand from an academic perspective,” says Bjork. “Historically, there are great painters who just persisted even though during their lifetimes they were impoverished. It’s a mystery what kept them going.” For Tiger Woods, “there was no push to have him practice; it was a reward if he got his homework done,” Bjork says. “Wayne Gretzky’s parents would have to go get him for meals; he was out there [on the ice] on his own.”

I can’t help wondering if the Dan Plan wasn’t too cold-blooded. McLaughlin grew to love golf, he says, but passion was never the project’s animating principle. “I was very serious about it, but it never became an obsession. At the end of the day, I could always walk away and say, ‘what’s next?’”

Cramped by a shoestring budget and flawed on multiple levels, the Dan Plan raised more questions than it answered about the road to mastery. But that—appreciating how much more there is to understand—is progress, too.