Malcolm Gladwell in The New Yorker:
Genius, in the popular conception, is inextricably tied up with precocity—doing something truly creative, we’re inclined to think, requires the freshness and exuberance and energy of youth. Orson Welles made his masterpiece, “Citizen Kane,” at twenty-five. Herman Melville wrote a book a year through his late twenties, culminating, at age thirty-two, with “Moby-Dick.” Mozart wrote his breakthrough Piano Concerto No. 9 in E-Flat-Major at the age of twenty-one. In some creative forms, like lyric poetry, the importance of precocity has hardened into an iron law. How old was T. S. Eliot when he wrote “The Love Song of J. Alfred Prufrock” (“I grow old . . . I grow old”)? Twenty-three. “Poets peak young,” the creativity researcher James Kaufman maintains. Mihály Csíkszentmihályi, the author of “Flow,” agrees: “The most creative lyric verse is believed to be that written by the young.” According to the Harvard psychologist Howard Gardner, a leading authority on creativity, “Lyric poetry is a domain where talent is discovered early, burns brightly, and then peters out at an early age.”
A few years ago, an economist at the University of Chicago named David Galenson decided to find out whether this assumption about creativity was true. He looked through forty-seven major poetry anthologies published since 1980 and counted the poems that appear most frequently. Some people, of course, would quarrel with the notion that literary merit can be quantified. But Galenson simply wanted to poll a broad cross-section of literary scholars about which poems they felt were the most important in the American canon.