The math that explains why Y2K is back in fashion

The curious calculation that explains why fashion trends keep coming back

By K. R. Callaway edited by Claire Cameron

If you’ve noticed a resurgence in low-rise jeans, baby tees, and velor sweatsuits among the cool kids, know that what you’re witnessing isn’t just the return of a trend, it’s math.

Fashion fans know that trends tend to resurface every 20 years, and a new analysis of more than 150 years of women’s clothing shows that this cycle isn’t just anecdotal: Trends in hemlines, necklines, and dress sizes actually become cool again about 20 years after their last stint in the spotlight.

“I’ve always been surrounded by this idea that fashion comes back and fashion is cyclical, so I started thinking: Is that actually true?” says Emma Zajdela, a postdoctoral researcher at Princeton University who led the new analysis. “I realized that what we found in the data was a perfect match with what was being said in the industry, so that was pretty amazing to us.”

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The analysis used data from the Commercial Pattern Archive, a digital database that stores tens of thousands of images of clothing designs dating back to the 1840s as well as photos from runway shows. Using these resources, researchers were able to create a comprehensive fashion database, containing more than 35,000 images of women’s clothing.

Zajdela and her team analyzed the main characteristics of women’s dresses over time. Looking along the vertical axis from head to toe, the researchers plotted how hemlines rose and fell in periodic curves over time and fit their results into a mathematical model.

“The mathematical model we use is quite simple conceptually,” explains Zajdela. “It’s based on this idea in psychology called optimal distinction.”

Optimal distinctiveness essentially means that people want to belong to a group while remaining unique in some way. When applied to fashion, this means that for a new trend or innovation to be successful, it must be different enough, but not too much, from existing things. People tend to want new and unique clothing, but they also generally don’t want to stray too far from what they’ve worn in the past or what others are wearing.

Looking for styles that are both familiar and different can lead some people to gravitate toward more nostalgic designs, especially for younger generations looking for fashion inspiration, because these styles are from a time period they haven’t directly experienced and therefore feel more “new.”

“Every 20 years you have a new generation of consumers who yearn for the past,” says Shawn Grain Carter, associate professor of fashion business management at the Fashion Institute of Technology, who was not involved in the study. “We love going back to the past to figure out how to…introduce something new to the next generation of consumers.” »

It is possible that the 20-year cycle will change in the future: it takes less time to produce new clothes and social media has given people access to more ideas, thus accelerating trends. But for now, the mathematical model holds up: there’s just a lot more diversity in the recent data, Zajdela says.

Having established that fashion trends can be described mathematically, researchers are interested in what similar models can tell us about other areas of human innovation.

“We have this example from fashion, but it shows how human creative efforts, or innovations, in general, can happen,” says Zajdela. “Many other types of innovations have the property of being different from the past, but not too much. »

The results were presented Tuesday at the American Physical Society’s World Physics Summit.

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