WEDNESDAY, May 31, 2023 (HealthDay News) -- Girls have long been thought to have a language advantage over boys as infants. But new research finds that boys make more vocalization sounds than girls do in the early months of life.
These squeals, growls and short word-like sounds such as “ba” or “aga” are precursors to speech, scientists say.
And baby boys do more of this “talking” than baby girls in the first year, researchers reported May 31 in iScience.
“Females are believed widely to have a small but discernible advantage over males in language,” said D. Kimbrough Oller, a professor at the University of Memphis in Tennessee. “But in the first year, males have proven to produce more speech-like vocalization than females."
However, “the girls caught up and passed the boys by the end of the second year,” Oller said in a journal news release.
Building on earlier research, the researchers amassed more than 450,000 hours of all-day recordings of nearly 5,900 infants. Recordings were analyzed automatically to count infant and adult utterances in the first two years of life.
The study found that male infants made 10% more utterances in the first year compared to females. In the second year, female infants made about 7% more sounds than males.
This was despite the fact that adult caregivers used more words when caring for girls compared to boys.
That boys are more active in general may be a reason they’re more vocal earlier, researchers said. But that theory might not hold because they remain physically active and yet not more vocal.
The findings might fit with an evolutionary theory that infants vocalize to express their wellness and improve their own odds of surviving, Oller suggested.
“We think it may be because boys are more vulnerable to dying in the first year than girls, and given that so many male deaths occur in the first year, boys may have been under especially high selection pressure to produce vocal fitness signals,” Oller said.
As death rates overall drop by the second year, “the pressure on special fitness signaling is lower for both boys and girls,” Oller said.
The study was partly supported by the U.S. National Institute on Deafness and Other Communication Disorders.
The U.S. National Institutes of Health has more on speech and language development.
SOURCE: iScience, news release, May 31, 2023