
A team led by Shiry Ginosar, PhD, is data-mining photos dating all the way back to 1905 in order to understand trends from different time periods. In total, they examined 37,000 digitized images pulled from 800 yearbooks from 26 states in the U.S. The researchers grouped the photos by decade to create an "average face" for the period, revealing trends such as hairstyles, glasses, and facial expressions. Particularly interesting is the evolution of smiling over the years.

The researchers also pinpoint hairstyle trends — such as '30s finger waves, the bouffants and afros of the '70s, and the long, straight hair of the 2000s. We wonder what other interesting findings will come out of studying this massive trove of photos; maybe the researchers can explain why some heartthrobs were always dreamy, and others once looked like this.
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