Researchers at UC Berkeley have collected some interesting data in regards to smiling in yearbook portraits over the past century. They looked at both men and women’s portraits to see how they evolved.
Researchers at the University of California, Berkeley have recently completed an intensive study on the evolution of smiling in yearbook portraits over the last 100 years.
The mammoth undertaking involved sifting through 150,000 high school portraits from the digital archives of school across America, with some of them dated as early as 1905.
After filtering out non-full-frontal portraits using machine vision, the number was narrowed down to 37,000 photos from 800 yearbooks in 26 cities.
The photos were then grouped by decade and merged into one composite image to create an “average” image for that decade.
The findings reveal that both men and women wore bigger and wider smiles over the years. Another finding was that that women “significantly and consistently smile more than men”, a fact that is already known.