Baby names drift like genes
Monday, 16 June  2003 

	The selection of baby names follows a predictable mathematical pattern (Pic: U.S. National Institutes of Health)

Mathematics and basic population genetics can be used to predict that no matter how unusual your baby name is today, it has a chance of becoming very common in the future.

The claim by Dr Alex Bentley of University College London and Matthew Hahn of Duke University in the U.S. are published in the June issue of the Royal Society's Biology Letters.

"Some parents today who invent some original name for their baby, like 'Grast', could - through simple random chance - unwittingly be determining the names of thousands of children 10 years from now," said Bentley, of the college's Centre for the Evolutionary Analysis of Cultural Behaviour, which uses biological ideas to understand cultural change.

Using British and U.S. government data, Bentley and Hahn tracked the popularity of the top 1,000 first names for baby girls and boys in the U.S. for every decade in the 20th century.

They found that a few names were thousands of times more popular than the majority with many uncommon names. They said the distribution followed an "elegant mathematical function," called a power law, that is maintained over 100 years, even though the population is growing.

Hahn and Bentley developed a model which closely predicts the distribution of name popularity over the last century. The model is based on the population genetics concept of 'random genetic drift', in which the frequency of genes in a population fluctuates according to chance, and where there is only a small population of breeding parents.

In their simulation, people randomly copied existing baby names, only occasionally inventing new names. "By its simplicity, this model provides a powerful null hypothesis for cultural change," wrote the researchers.

"We can't predict which newly-invented name will be the name for thousands of babies a decade from now, but we can with all certainty predict that some baby somewhere is being given an original name that will someday become highly popular," said Bentley. "Through basic population genetics, we can predict about how common the most popular one will be."

"We found that girls have a 40% higher chance of getting a unique name than boys," said Hahn. "I'd bet that this has a lot to do with life in a patriarchal society, where boys more often get traditional names. It might also show the 'playground effect' - boys with unusual names are going to be teased mercilessly."

The researchers argue their study has implications for cultural changes in general. "In the social sciences, there is currently no consensus on the mechanism by which cultural elements come and go in human society," they wrote.

While social scientists often assume there is a 'reason' why something becomes popular, they argue that sometimes things may just become popular by "dumb luck" - and acquire their meaning afterward.

"For example, some first names have upper- or working-class connotations," the researchers said. "They probably became popular in their respective economic classes before becoming stereotypical."

They also add that random copying could potentially explain power law distributions in other cultural realms, including the links on the World Wide Web.

Anna Salleh - ABC Science Online

More Info?
How many fish in the sea? Check their genes, News in Science 4 Nov 2002
Mysterious inbred cattle have survived long term, News in Science 18 Jan 2001
Web to nowhere, News in Science 19 May 2000

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