Toddlers who spend a lot of time in a noisy environment may have a harder time learning to speak, a small study suggests.
That's because background noise - especially the kind that comes from voices on the television or radio - can make it tough for young children to learn new words, said study co-author Brianna McMillan of the University of Wisconsin-Madison.
"Either turning off the TV and radio or turning them down may help language development," McMillan said by email.
"In addition to trying to be aware of how noisy their home may be, I would encourage parents to take advantage of any quiet time they may have - quiet moments can be great opportunities to talk to children and encourage exploration and learning," McMillan added.
To understand how background noise influences language development in toddlers, McMillan and colleagues did three experiments with a total of 106 kids ranging in age from 22 to 30 months.
In each experiment, toddlers listened to sentences featuring two new words. Then they were shown the objects the words identified. Afterward, researchers tested kids to see if they remembered the new vocabulary.
In the first experiment, 40 kids aged 22 to 24 months heard either louder or softer background speech when learning the new words. Only toddlers who were exposed to less background noise successfully learned the new words, according to a report online July 21 in Child Development.
Then, researchers repeated the experiment with a different group of 40 children who were slightly older - 28 to 30 months. Again, kids only absorbed the lesson when there was limited background noise.
For the third experiment, kids heard two new words in a quiet environment. Then they were taught the meaning of these words as well as two additional words with the same level of background noise that impaired learning in the previous experiment.
The children in this last situation only learned the new words and their meanings if they had initially heard the new vocabulary in a quiet setting. This suggests that hearing words in a quiet environment without distracting background noise, may help children learn, the authors conclude.
One limitation of the study is that researchers only exposed children to one type of background noise, which might mean the results would be different in other environments, the researchers note.
Even so, the findings are consistent with other research on language development that has found background noise can inhibit language development, said Renata Filippini, a researcher at the University of Sao Paulo in Brazil who wasn't involved in the study.
"For optimal language development, controlling background noise is highly recommended, especially during specific learning moments, like during a story telling activity or during feeding times," Filippini said by email.
Parents also need to understand that infants and toddlers aren't as good at tuning out distractions as adults, said Suneeti Nathani Iyer, a speech and language researcher at the University of Georgia in Athens who wasn't involved in the study.
"When adults are in the presence of a lot of background noise, we are able to ignore it and focus on what is relevant," Iyer said by email. "Infants appear to not be as good at filtering out background noise and focusing on relevant information."
Child Development 2016.