That Coleman in 1959 saw a direct link between teen culture and high school achievement is significant. Though the first public high school opened in Boston in 1821, for more than a hundred years, the majority of American teens were otherwise engaged. Most didn’t hold a high school diploma until 1940. The byproduct of more universal schooling—or perhaps its main product—was the American teenager, “a New Deal project” much like the Hoover Dam, wrote cultural critic Thomas Hine.

Actually, Hine noted, the word “teenager” first appeared in a 1941 Popular Science article. Compulsory education gave rise, inevitably, to mid-20th-century teen culture, and in quick succession, to nearly every cultural artifact we now associate with teens, most of them tied to breakthroughs in technology. Cheaper automobiles, color printing, and better amplification brought us car culture, comic books, and pop music—who can imagine a crooning Frank Sinatra screaming his way through the 1942 Paramount sessions? A generation later, another technological trio—birth control pills, synthesized LSD, and multitrack recording—brought us sex, drugs, and rock-and-roll.