At 13, an age when most boys want to learn the guitar, Gary Marcus, decided he wanted to be a scientist. Twenty-five years later he had become one of the country’s best known cognitive psychologists, with major papers and three general-interest books on the workings of the human mind and a position running New York University’s Center for Language and Music.

For any adult learning an instrument or a new language is terrifying. For a cognitive scientist, it can also be downright depressing. Humans have an early childhood window to acquire such skills easily, according to a long-held tenet in his profession, and it’s a window that closes quickly. Then there is the issue of innate ability. While no single gene can explain Beethoven, Yo-Yo Ma or “Waterloo Sunset,” Dr. Marcus does believe in natural talent, he said, or at least in the certainty he doesn’t have any.

Despite those misgivings he allowed himself one year of dedicated practice, armed with instruction books, a $75 Yamaha acoustic bought on eBay and one thing few adult music students have at their disposal: a year’s sabbatical.

Three years later he has chronicled his journey in a new book, “Guitar Zero: The New Musician and the Science of Learning” (Penguin). Like Daniel J. Levitin’s “World in Six Songs: How the Musical Brain Created Human Nature” and Oliver Sacks’s “Musicophilia,” “Guitar Zero” investigates the intersection between neuroscience and music. But the thread here is Dr. Marcus’s own often frustrating attempts to learn guitar. It’s the sort of book where Steven Pinker (Dr. Marcus’s mentor and collaborator) mixes with K. Anders Ericsson (the psychologist most associated with the “10,000 hours” theory of expertise) and Tom Morello (the lead guitarist from Rage Against the Machine)....