I’m not sure why I’m suddenly compelled to post about clothing again, but the Washington Post’s Roberto A. Ferdman has this interesting piece on the subject:

Look around you, and you’ll likely notice a sea of different outfits. You might see similar articles of clothing — even the same ones — worn by different people, but rarely do you find two pairings of tops, bottoms, shoes, and accessories that are exactly alike.

That wasn’t always the case, said Deirdre Clemente, a historian of 20th century American culture at the University of Nevada, Las Vegas, whose research focuses on fashion and clothing. Americans were far more formal, and formulaic dressers, not all that long ago. Men wore suits, almost without fail — not just to work, but also at school. And women, for the most part, wore long dresses.

Clemente has written extensively about the evolution of American dress in the 1900s, a period that, she said, was marked, maybe more than anything else, by a single but powerful trend: As everyday fashion broke from tradition, it shed much of its socioeconomic implications — people no longer dress to feign wealth like they once did — and took on a new meaning.

The shift has, above all, led toward casualness in the way we dress. It can be seen on college campuses, in classrooms, where students attend in sweatpants, and in the workplace, where Silicon Valley busy bodies are outfitted with hoodies and T-shirts. That change, the change in how we dress here in America, has been brewing since the 1920s, and owes itself to the rise of specific articles of clothing. What’s more, it underscores important shifts in the way we use and understand the shirts and pants we wear.

I spoke with Clemente to learn more about the origins of casual dress, and the staying power of the trend. The interview has been edited for length and clarity.

Let’s start by talking a bit about what you study. You’re a historian, and you focus on American culture as it pertains to fashion. Is that right?

I’m a cultural historian. I’m a 20th century expert, so don’t ask me anything about the Civil War. And my focus is clothing in fashion. So I’m a little bit of a business historian, a little bit of a historian of marketing, and a little bit of a historian of gender. When you kind of mix all of those things together, all those subsections of history, you get what I study.

So that scene from “The Devil Wears Prada,” when Meryl Streep criticizes Anne Hathaway for believing she isn’t affected by fashion, it must resonate with you.

Well you know, it’s just so true. People say, “Oh well, you know, I don’t care about fashion.” They go to the Gap, they go to Old Navy, and they all dress alike, they wear these uniforms. The thing that I really harp on is that, that in and of itself is a choice, it’s a personal choice, because there are many people who don’t do that. In buying those uniforms, you’re saying something about yourself, and about how you feel about clothing and culture. There is no such thing as an unaffected fashion choice. Anti-fashion is fashion, because it’s a reaction to the current visual culture, a negation of it.

How would you characterize the way Americans dress today? What’s the contemporary visual culture like now?

Well, I would certainly say that there are, above all, so many more choices than there have ever been before. There’s also a tendency like never before to alternate styles. People will one day dress very conservatively and then the next day wear something much more dramatic, much less formal.

There’s a clear trend toward individualization, as opposed to homogenization. There are so many different kinds of social and cultural personas that we can put on, and our clothes have become extremely emblematic of that. And the thing is, even if you don’t have a lot of money, you can now dress freely, individually.

You have written about how American dress, perhaps more than anything else, is characterized by how casual it is. What do you mean by that?

There’s this fashion theorist who wrote in the 1930s about how in capitalist societies, clothing serves as this way to jump in and out of socioeconomic class. Now, he was writing at a time when people were still really trying to jump up, and could feign wealth. You could buy a nice-looking suit and make it seem like you were a lot more wealthy than you actually were then. But in the second half of the 20th century, what we’ve seen is people doing just the opposite.

Americans have come to dress casually in a way that is very interesting as a historian. When you look back at old pictures of students, it’s jarring. We used to dress so formally, just to go to class.

Are there points, chronologically, that stand out? Times that were particularly important for the migration toward less formal wear?

I think there are two key points in the 1920s. The 1920s were really important for this shift.

In the 1920s, when women really broke away from dresses and matchy matchy suits, and instead began to use sweater vests and other outfits, versatility entered the minds of buyers. At that point, people began to mix and match, wear more sweaters, more gored (which is a kind of skirt).

By the late 1920s, very few college men wore suits to class. The rise of the sports coat is an incredibly underlauded change in American culture. Because once boys started wearing sports coats instead of suits, men’s outfits became more versatile, they moved away from ties, they wore all sorts of different things, like sweaters, with their jackets.

If so much of this was predicated on shifts that happened in the 1920s, was there nothing impactful that happened thereafter?

Pants on women. You cannot talk about the rise of casual dress without talking about the rise of pants of women. You first saw it in elite women’s schools, such as Wellesley and Vassar. Once women were wearing pants and even jeans on campus and to class, which happened starting in the 1930s, things really began to change. Even though it wasn’t yet happening on co-ed campuses, because of the mix of genders, and formality that persisted around that, it was still a big deal.

World World II was also revolutionary for dress. The war brought about a whole culture of dress that didn’t exist before. Women wore what they wanted, because it didn’t matter — they were on their way to the victory garden — or because they were working at factories, where practicality was more important.

So in the aftermath of World War II, more casual outfits became commonplace?

Yes, although there was a slight backslide in the late 1940s, where we saw a bit of reluctance around it. In 1948, Christian Dior put out a new look in the United States, which featured long skirts that were tight-waisted. That was a Parisian couture influence, though, and it didn’t stick. Women either weren’t really buying it, or wearing it. It had about a two-year lifespan, and then the college girls migrated toward the freedom of articles like pants and less cumbersome dresses. They had experienced these, and they weren’t going to go back to more uncomfortable clothing.

Then in the 1950s, you really start to see stay-at-home moms wearing casual wear in the house — shirts, pants, jeans, even T-shirts. And it really took off from there.

The only thing I will say is that there’s still a bit of a gender hangover, where women are singled out for wearing clothing normally associated with men.

Like the boyfriend jean?

(Audible sigh). Yes.

There’s something in women buying “men’s clothing” that still irks a lot of people. I have been shocked at the e-mails I have gotten. People like to say that casual dress isn’t about freedom, that it’s about laziness. But that’s hilarious, especially to me as a historian, because it simply isn’t true.

There’s something called collective selection. And what it is, is the idea that no longer is it the rich people telling the poor people how to dress, no longer is it that the poor people want to wear what the rich wear. Nowadays it’s a group decision. Because class is so wishy washy today, since everyone thinks that they’re middle class, the collective selection is what is acceptable in different scenarios — the office, the church, the classroom, etc. It’s decided by the group.

What about the development of American fashion in comparison to that elsewhere? Have we gone further down the road of casual dress than other cultures?

Oh, I mean, absolutely. I think that American culture is now associated with casual dress on a global scale. On sort of the world stage, where American culture is so prominent, many countries emulate the way people in the United States dress, and that’s almost inevitably more casually than the way people dress in those places. The version of casual elsewhere, in Europe especially, it just never gets as down and dirty as the American version. Their version of casual is still a scarf and a stylish leather jacket, whereas ours is a starter jacket and jeans.

The American love of sportswear and comfortable clothes has redefined the limits, and it’s affecting the limits elsewhere too, since others emulate us.

Can I ask what might be an obvious question, at least to you. What makes something casual, and something else formal?

That’s an obvious question, and an awesome question. The answer inevitably is tied to history. I can look at something and say “Oh, the history of that article of clothing is such and such, and that history is tied to wealth.” Or, if you look at, say, the turtleneck, and understand that it comes from ski-wear, or flip flops, and realize that they were originally shower-wear, often used by servants, it changes the context in which you understand the clothing.

More broadly, and kind of simply, fit and fabric also tend to be good indicators. The fit of casual clothes tends to be looser, and the fabric tends to be lighter, because there’s less of it. There’s also less covering of the skin in casual wear. When you think of formal attire, it mostly covers the vast majority of the body.

Also, the connotations of it, which, again, are rooted in history. That’s the cool thing about clothing, which people don’t realize. When someone is like ‘those shoes are cool but I don’t know if they’re appropriate for this wedding,’ their opinion is the product of years, even decades of understanding.

Even at the office, we’ve shed some of the more formal, traditional understandings of what’s okay to wear. You mentioned Steve Jobs, but Silicon Valley as a whole is kind of redefining office wear, is it not?

They are absolutely the spearhead of business casual. They were the first people to do away with dress codes at the office.

But this isn’t your typical business casual. Every time I see that phrase I look it up, and it’s like khakis and a button down still. This is more like business CASUAL, or casual business, where casual is the emphasis.

Oh, I love that. It’s this evolution of casual, and even of business casual. In the 1990s, it was derivative of business, and now it’s derivative of casual. It’s amazing for me to see.

Why does it bend toward casual?

I think we dress more casually because we can, because in American culture perennial appearance has become an expression of individuality and not social class to the degree that dressing up is dressing up the socioeconomic ladder. I think that we dress more casually because it’s a middle ground for Americans. I mean look at the presidential candidates. Donald Trump has his own, albeit mediocre quality, shirt and tie line. It’s all about standing out and yet fitting in.

The modern market allows us to personalize that style. Casual is the sweet spot between looking like every middle class American and being an individual in the massive wash of options. This idea of the freedom to dress in a way that is meaningful to us as people, and to express various types of identity.

I know that you’re a historian, and traditionally look into the past, but I’m going to ask you to look into the future. Where is this trend toward casual dress taking us?

How about I make a prediction about a specific technology that’s been long overdue? I don’t know if it will happen, let alone sometime soon, but self-cleaning fabrics, I think that will be a thing. At the very least it should be.

I have to say, self-cleaning fabrics are about as casual as it gets.

Let’s just say I probably wouldn’t put my money in dry cleaning if I had some extra money to spare and wanted to invest in something. Those sorts of things are going to die out.

There was this very cool Italian futurist who in the 1930s made a prediction about what fashion would be like 100 years from then. His prediction was that everyone would dress in uniforms. But that’s the complete opposite of what has happened.  And I don’t think people will be dressing in uniforms anytime soon. Clothing will instead continue to be a way to project individuality and our own personal alliances to the broader culture.