Trends in popularity of baby names and dog breeds can help understand evolutionary change

Maverick was first used as a baby name after a TV show called “Maverick” aired in the 1950s, but its popularity skyrocketed in 1986 with the release of the movie “Top Gun.” Today it is even used for baby girls.

The name Emma peaked in popularity in the late 1800s, declined precipitously through the first half of the 1900s, and then reverted to being one of the most popular names of the early 2000s. Linda peaked some part in the late 1940s and Daniel in the mid-1980s. But each rise in popularity was followed by an equally steep decline.

So what’s in a name; or, at least, what’s in a baby name trend? University of Michigan evolutionary biologist Mitchell Newberry has found that the more popular a name becomes, the less likely future parents are to follow suit. The same goes for popular dog breeds: Dalmatians are ten times more popular today than they were in the 1990s.

Newberry, assistant professor of complex systems, says examining trends in the popularity of baby names and dog breeds can be a proxy for understanding ecological and evolutionary change. The names and preferences of dog breeds themselves are like genes or organisms competing for scarce resources. In this case, the scarce resources are the minds of parents and dog owners. His results are published in the journal Nature Human behavior.

Newberry looks at frequency-dependent selection, a kind of natural selection in which the tendency to copy a certain variant depends on the current frequency or popularity of that variant, regardless of its content. While people tend to copy the most common variant, everyone ends up doing pretty much the same thing. But if people become less willing to copy a variant, the more popular it becomes, this leads to a greater diversity of variants.

“Think about how we use millions of different names to refer to people, but we almost always use the same word to refer to baseball,” Newberry said. “For words, there is a pressure for conformity, but my work shows that the diversity of names results from pressures against conformity.”

These trends are common in biology, but difficult to quantify. What the researchers have is a comprehensive database of baby names over the past 87 years.

Newberry used the Social Security Administration’s baby name database, itself born in 1935, to examine the frequency dependence of first names in the United States. He found that when a name is the rarest – 1 in 10,000 births -; it tends to grow, on average, at a rate of 1.4% per year. But when a name is most common; more than one in 100 births; his popularity is declining, on average, at 1.6%.

This is really a case study of how boom and bust cycles alone can disadvantage common types and promote diversity. If people are always hungry for new things, it will create a lot of new things. Every time a new thing is created, it gets promoted, and so rarer things become more frequent and you have more diversity in the population.”

Mitchell Newberry, evolutionary biologist, University of Michigan

Using the same techniques they applied to baby names, Newberry and his colleagues examined dog breed preferences using a database of purebred dog records from the American Kennel. Club. They found boom-bust cycles in dog breed popularity similar to boom-bust cycles in baby names.

The researchers found a Greyhound boom in the 1940s and a Rottweiler boom in the 1990s. This shows what the researchers call negative frequency-dependent selection, or anti-conformity, which means that as the frequency increases, the selection becomes more negative. This means that rare dog breeds at 1 in 10,000 tend to gain popularity faster than dogs already at 1 in 10.

“Biologists fundamentally think that these frequency-dependent pressures are fundamental in determining so many things,” Newberry said. “The long list includes genetic diversity, immune evasion, host-pathogen dynamics, the fact that there is essentially a one-to-one relationship between males and females – and even what different populations think is sexy.

“Why do birds like long tails? Why do bamboo trees take so long to flower? Why do populations divide into different species?

Conformity is needed within species, says Newberry. For example, scientists can change the order of genes on a fly’s chromosomes, and that doesn’t affect the fly in any way. But that doesn’t happen in nature, because when that fly mates, its genes don’t match those of its mate and its offspring won’t survive.

However, we also need non-conformism, he says. If we all had the same immune system, we would all be susceptible to the same diseases. Or, says Newberry, if the same species of animal all visited the same patch of land for food, they would quickly destroy each other.

“Life is this dance of when do we have to be consistent and when do we have to separate?” he said. “Natural selection is incredibly hard to measure. You ask, for an entire population, who lived, who died, and why. And that’s just a crazy thing to try to ask. In contrast, in names, we know literally every name. for the whole country for a hundred years.”