With their standard formats and widespread availability, high school yearbooks represent a historical data set of 20th-century style. They also capture how our tendency to smile in photographs has intensified over time. A new study from researchers at University of California, Berkeley, examines how smiling became the expression of choice for portraits, analyzing photographs from American yearbooks dating from 1905 to the 2010s.
“A Century of Portraits: A Visual Historical Record of American High School Yearbooks“ was published last month on arXiv, the open-access online research archive hosted by Cornell University Library. At the beginning of the century, photography was established as a medium, but still relatively new and mostly a luxury. The stoic portrait poses of the 19th century still reigned. Shiry Ginosar, the study’s lead author, stated in the MIT Technology Review that in the early 1900s, “etiquette and beauty standards dictated that the mouth be kept small—resulting in an instruction to ‘say prunes’ (rather than cheese) when a photograph was being taken.”
The study involved sourcing 37,921 front-facing portraits from 949 yearbooks in 27 states. These were superimposed to generate “average” faces, which were then analyzed with a “machine-vision” algorithm to look at the lip curvature, which resulted in a trend towards more, and wider, smiles as the decades progressed. The fashion of yearbook photographs also changed, growing less formal as they became more accessible. The researchers note that in the early 1900s, it was just under 10% of the country that was graduating from high school, compared to 50% at the end of the 1960s, and for much of the early 20th-century the people graduating look white.
The researchers add that their study follows and confirms the data in Christina Kotchemidova’s Why We Say “Cheese”: Producing the Smile in Snapshot Photography. In that paper, Kotchemidova argues that Kodak and its marketing for happy photography moments coincided with the availability and speed of photography, encouraging the proliferation of smiles. The UC Berkeley researchers write that their “figures corroborate Kotchemidova’s theory and demonstrate the rapid increase in the popularity and intensity of smiles in portraiture from the 1900s to the 1950s, a trend that still continues today; however, they also reveal another trend — women significantly and consistently smile more than men.” Also worth noting is that dental care greatly improved over the 20th century, and perhaps people were more willing to flash their straight, fluoride-bright teeth.
While the century of smiles is interesting, it’s the demonstration of their algorithm’s analysis of thousands of digitized images that’s at the center of the study. As the researchers conclude, they “believe that the use of largescale historical image datasets such as ours in conjunction with data-driven methods, can radically change the methodologies in which visual cultural artifacts are employed for humanities research.”
A Century of Portraits: A Visual Historical Record of American High School Yearbooks is available to read online at arXiv.