A new paper at the Bureau of Economic Research argues that the shift in popular music from the Tin Pan Alley of Irving Berlin to the rock & roll of John Lennon produced measurable changes in the songwriter labor market. Writes the University of Chicago's David Galenson:

"Irving Berlin, Cole Porter, and other songwriters of the Golden Era wrote popular songs that treated common topics clearly and simply. During the mid-1960s Bob Dylan, John Lennon, and Paul McCartney created a new kind of popular music that was personal and often obscure. This shift, which transformed popular music from an experimental into a conceptual art, produced a distinct change in the creative life cycles of songwriters. Golden Era songwriters were generally at their best during their 30s and 40s, whereas since the mid-'60s popular songwriters have consistently done their best work during their 20s."

Makes sense. When passion and energy are valued more highly than structure and cogitation, young people always have an edge. Impressionist painters bloomed early. Shelley, Coleridge, Wordsworth and Keats, the English Romantic poets who defined artistic emotion, all did their best work in their 20s. Keats and Shelley died young, and Wordsworth and Coleridge were worthless after 30.

But I wouldn't look just at the supply side. The careers of songwriters changed also because the audience changed. Music consumers were older before World War II. There was no youth culture as we know it. When American baby boomers grew up and found themselves with more money than any teenagers in the history of the world, they didn't want to buy music written by old guys. Maybe the changing audience altered the demanded material, which changed the kind of people needed to produce it.

The whole Galenson paper is here. It looks like it's behind a pay wall for the public.  

What I really want to know, however, is how the career cycle of rock & roll artists affects the price of Bowie Bonds.