In 1940, the anthropologists Jane Richardson and Alfred Kroeber examined pictures of catalogues, magazines, and drawings dating back to the 1600s in an attempt to find trends in the cuts and styles of women’s dresses. What they produced were fascinating graphs of evolving social mores, with periods of plunging necklines quickly succeeded by buttoned-up decades of modesty, and vice-versa. One particularly entertaining chart shows generally Amish-length skirts throughout history — save for a racy, rapid shortening during the libidinous 1920s.

Skirt lengths by decade, from 1600 to 1940. (Richardson and Kroeber)

In 1976, University of Washington economist Dwight E. Robinson sought to apply the same technique to fashion trends in the opposite sex—specifically, in men's “facial barbering.”

For the study, published in the American Journal of Sociology, he examined the period between 1842 and 1972, the years of continuous weekly publication of the Illustrated London News. Since this was the “world’s most venerable pictorial news magazine,” it would serve as his sole source.

With the acknowledgement that the “gentlemen of the News” were largely limited to prominent members of society, he set about counting the frequency with which five different facial hair styles appeared: sideburns alone, sideburns and mustache, a beard (“any amount of whiskers centering on the chin,” in case you were confused), mustache alone, and clean-shaven. He excluded pictures of royalty, models, and non-Europeans, and gathered about 100 images for each year.