Fashion insiders and beauty magazines have long cited the “20-year-rule” — the idea that clothing trends often resurface every two decades.
According to Northwestern University scientists, that observation isn’t just anecdotal. It’s a mathematical reality.
In a new study, the Northwestern team developed a new mathematical model showing that fashion trends tend to cycle roughly every 20 years. By analyzing roughly 37,000 images of women’s clothing spanning from 1869 to today, the team found that styles rise in popularity, fall out of favor and then eventually experience renewal.
Along with supporting common perceptions about the life cycles of fads, the researchers say these results could help explain how new ideas spread in society.
The study’s lead author Emma Zajdela recently presented these findings at the American Physical Society (APS) Global Physics Summit in Denver.
What’s new
“To our knowledge, this is the first time that someone developed such an extensive and precise database of fashion measures across more than a century,” Zajdela said. “We have some very interesting results, including that the cycle we uncovered in the data (20 years) matches industry knowledge. Historically, the lack of data posed a barrier to explicit quantitative study of this system.”
The researchers
When this work was conducted, Zajdela was a Ph.D. candidate at Northwestern’s McCormick School of Engineering, where she was advised by Daniel Abrams, a professor of engineering sciences and applied mathematics at McCormick and co-director of the Northwestern Institute on Complex Systems. Now, Zajdela is a postdoctoral fellow at Princeton University and a research fellow at the Santa Fe Institute.
Zajdela and Abrams coauthored the study with Alicia Caticha, an assistant professor of art history at Northwestern’s Weinberg College of Arts and Sciences, and Jeremy White and Emily Kohlberg, who were both members of Abrams’ research group.
How they did it
To conduct the study, the researchers compiled one of the most comprehensive quantitative datasets of fashion ever assembled. Drawing from historical sewing patterns from the Commercial Pattern Archive at the University of Rhode Island and runway collections, the team analyzed tens of thousands of garments dating back to the late 1800s.