Here’s a quiz: Rock musicians tend to peak early because a) most commit suicide before age 35; b) those years of drug use don’t exactly sharpen your brain; or c) rock ‘n’ roll is a conceptual, as opposed to an experimental, art form.

If you guessed C, the University of Chicago economist David Galenson would agree with you. In a working paper deposited at the National Bureau of Economic Research, “From ‘White Christmas’ to Sgt. Pepper: The Conceptual Revolution in Popular Music,” Mr. Galenson argues that Irving Berlin, Cole Porter, and George Gershwin were “experimentalists,” who tried to write songs that were clear and easy to understand, were craftsmen rather than artistic geniuses, worked by trial-and-error, and did their best work late in life.

By contrast, Bob Dylan, the Beatles, and the Beach Boys were “conceptualists,” who made dramatic breakthroughs early, writing music that was personal, introspective, and often technically “messy.” By studying various top-100 lists, Mr. Galenson then concludes that, as his theory would predict, the earlier musicians wrote their best songs in their 30s and 40s, while the artists of the 1960s had their greatest hits in their 20s.

Mr. Galenson acknowledged that experts in the fields he has written about haven’t exactly embraced his ideas. They “hate the idea that somebody is doing this systematically,” he said.

A professor of psychology at the University of California, Davis, who has studied creativity, Dean Simonton, said in an e-mail that “few of [Mr. Galenson’s] studies have survived peer review” because they seldom stand up to “serious methodological and conceptual scrutiny.” Mr. Simonton acknowledged that he had favorably blurbed Mr. Galenson’s “Old Masters and Young Geniuses: The Two Life Cycles of Artistic Creativity.” But he added about Mr. Galenson, “Nonetheless, I do believe he has fantastically overstated his case.”