- How many Mildreds did you go to school with?

(crickets chirping) What about Norman?

How many Normans or Ednas or Elmers?

If you're under 60 years old, the answer is probably none.

Although these were all very popular baby names in the early 20th century, they've steadily fallen out of fashion and are now almost extinct.

When you hear names like Gladys or Herbert or Doris, you probably automatically think of old people, but why is that?

Is there something about the phonetics of the words themselves that create that association?

Probably not since at one point, a lot of people thought they sounded like great baby names.

In fact, Mildred was in the top 10 baby names for over 20 years, but hasn't cracked the top 1,000 since 1984.

Linguists have been studying the science of first names for a long time, and though what's behind the particular parents' choice is deeply personal and often opaque, there are certain trends in baby naming that can reveal a lot about the values and direction of a society.

I'm Dr. Erica Brozovsky and this is "Other Words."

(lively music) (train chugging) - "Other Words."

- And what is your name?

- Butch.

- What does it mean?

- I'm an American, honey, our names don't mean (beep).

- The irony of this iconic line is that Butch is short for Butcher, popularized by the famous Western outlaw Butch Cassidy.

Appending it to a character who goes on the run after killing someone was surely no accident.

Americans may think of their names as just collections of phonemes that their parents thought sounded nice, but names, known as anthroponyms, have etymologies just like any other words.

If you look up their meaning on one of those baby naming websites, you'll probably find words like strength or wisdom, which is funny because newborns are pretty uniformly weak and stupid.

My name, Erica, is the feminine form of Eric, which comes from the old Norse Eirikr, meaning eternal ruler, ever powerful.

(dramatic music) But my parents say they chose Erica because my mom read the name in a book and liked it.

They had no idea what the meaning was, but I guess it worked out in my favor.

Literal name meanings are still relevant in many cultures around the world.

For example, in China, a baby's given name might be chosen to complement family names.

So if the family name is Liu, the parents might name their child Qing.

If a son's name is Song, they might name his sister Mei.

But in America, literal meanings take a backseat to more subjective associations.

And a big one is pop culture.

Sociologist Michelle Napierski-Prancl cross-referenced the Social Security Administration's archive of baby names with Billboard's Hot 100 for each year, and found that songs with a female name in the title correlated with a spike in that name's popularity, from The Beatles' "Michelle" to Toto's "Rosanna."

Parents also get inspiration from the celebrities themselves with the names of singers, athletes, and politicians seeing modest but perceptible bumps in popularity that correspond with news-making events.

Even fantasy franchises can influence naming trends.

When Millennials started to reach childbearing age in the 2010s, we saw a lot of Harrys, Hermiones and Lunas.

Sorry, Ron.

And the popularity of "Game of Thrones" set off a wave of Tyrions, Briennes and Aryas.

Though all those parents who named their kids Daenerys may have wanted to wait and see how the show ended first.

(people screaming) (booming sound) Religion might also play a role.

In fact, according to some sources, the most popular names in the world are Mohammed and Maria.

And while it's true that many of the top American names have biblical roots, it's unclear whether that reflects a religiosity in the parents or is just popularity begetting popularity.

Whether it's friends, relatives, or celebrities, the more people you know with a certain name, the safer it is to give it to your child.

Human culture, like genetics, is based on copying.

It's a lot like genetics.

In fact, a study by Matthew W. Hahn and R. Alexander Bentley used baby name trends to illustrate how changes in culture follow a similar pattern to genetic drift.

Just as successful genes duplicate themselves, popular names are duplicated by new parents.

A number of these parents may make small adjustments, an alternate spelling here, an extra syllable there.

If those adjustments are successful, they can, like genetic mutations, duplicate and spread.

You can see the drift in long-term trends.

The big classical names are still popular, but definitely in decline.

Over the last century, American naming conventions have become more diverse and unpredictable.

1/3 of babies born in 1880 were given a top 10 name.

By 2020, only 7% were.

Some of that may be due to the influence of immigrants and non-white ethnicities.

However, there may be more psychological trends at play.

Harvard sociologist Stanley Lieberson has suggested that ever since the Industrial Revolution, Western culture has shifted away from a reliance on extended families and therefore, places less value on older relatives.

It's not as common for babies to be named after their grandparents or aunts or uncles.

And as society becomes more individualistic and youth oriented, new parents deliberately avoid names that sound old.

Although Elon Musk may have taken it a bit far with X AE A-12.

Today, rates of unique baby names, names given to one and only one child per year, are at an all-time high.

And leading that statistic are African American parents who beginning in the 1960s began altering and inventing names at a rapid pace.

Many sociologists see this trend as an assertion of cultural identity and a repudiation of white Anglo traditions.

The last few decades have also seen an increase in androgynous and gender-flexible names, although this probably has little to do with politics.

In fact, androgynous names are increasing faster in red states than blue, perhaps because liberal parents tend to be older and therefore, less open to breaking conventions.

Furthermore, names that break gender rules only tend to go in one direction.

Many male names have shifted to be almost exclusively used for girls, especially ones ending in the diminutive E sound, like Lindsay, Leslie, Courtney, and Hillary.

We can see it happening in real time with Charlie, which only recently became female dominant.

But there are very few reverse examples of traditionally feminine names being given to boys.

Apparently, there's still more stigma in men being perceived as feminine than vice versa.

When you think about it, it makes total sense that cultural values should be reflected in baby names, even if only subconsciously.

Parents are expressing their dreams of who they want their child to be, and what role they'll play in the world.

They want their kids to fit in, but also stand out.

But there's still hope for Norman and Mildred.

According to name experts Sophie Kihm, it takes about 100 years for an old-fashioned name to become trendy again.

You just have to wait for all the current Normans and Mildreds to die out, and then eventually, the name loses its association with old people and feels fresh and new, which means sometime around 2120,