After the Great Crash of 1929, more and more Americans — not just adventurous students and youngsters — found themselves sticking out their thumbs in search of work and shelter. In perhaps the era's most notable depiction of hitchhiking, the hero of John Steinbeck's "Grapes of Wrath," Tom Joad, is introduced merely as "the hitch-hiker" (though he uses the more straightforward method of asking, "Could ya give me a lift, mister?") Those who didn't hitchhike personally may have learned the practice from the movies. In "It Happened One Night" (1934), the character played by Clark Gable explains that he's going to write a book about proper thumb technique, called "The Hitchhiker's Hail." He boasts:
It's all in that old thumb, see? Some people do it like this. [He waves his hand quickly back and forth, like a "Hello."] Or like this. [Another "hello," but a long, sweeping motion.] All wrong. Never get anywhere. Yeah, boy, but that old thumb never fails.
The movie became a major hit, the first to win all five major Academy Awards, and by 1937 the scene had been parodied by both Laurel & Hardy and Looney Tunes. In 1938, perhaps to improve on Gable's technique, two young men from Maine even constructed a mechanical thumb to do their thumbing for them.
Eventually, thumbing — as it was sometimes called — spread abroad. At first hitchhiking was considered to be strictly an American mode of transportation — a 1927 Glasgow Herald article described the word hitch-hiking as "the latest curiosity born out of the linguistic genius of the Yankee." Then in the 1930s, Europeans, too, began sticking out their thumbs. In 1939, British novelist Nicholas Monsarrat had one character who "thumbed [his] way across England in a day-and-a-bit," and in 1940 the London Times noted "the beseeching thumb" of the Registered Collegiate Thumbers. French travelers also got in on the act, though as the Los Angeles Times noted in 1938, in France, "Thumbing a ride is called auto-stop, and so far it has proved rather unsuccessful because of the few automobiles on French roads." By 1980 hitchhiking was so popular in Europe that Greece's entry in the Eurovision song contest was the hitchhiking anthem "Autostop," and the accompanying dance routine involved the singer repeatedly sticking out her thumb.