Noisy Places May Delay Kids' Speech
Infants Can't Separate Words From Loud Background Noise
April 5, 2005 -- Your child may take longer to learn to talk if he or she spends a lot of time near a blaring TV or in a cacophonous day care center, a new study suggests.
Infants can't tell spoken words from background noise unless the words are much louder than the noise, finds psychologist Rochelle Newman, PhD.
Newman is director of the language perception and development labs at the University of Maryland. She's interested in how children learn to talk and what this means for brain development. So she set up an interesting experiment.
Newman studied 100 infants at ages 5 months, 9 months, or 13 months. She tested how well the infants reacted to the sound of a woman speaking their name or unfamiliar names in the presence of background noise.
The infants listened longer to their names when the voice was more intense than the background noise.
Even the youngest children could do this. But they could only do it if the background noise was much softer than the sound of their own names.
"The 5-month-olds could separate the streams of conversation and focus on the voice calling to them if the background was at a level you might find in a romantic restaurant with soft and intimate conversations," Newman says in a news release. "But at that age the kids couldn't isolate the foreground voice if the noise level nearly doubled -- what you might hear in a crowded fast food restaurant."
By 13 months of age, the children were much better at separating the streams of conversation at both noise levels.
This means that kids who spend a lot of time in noisy places -- homes with the TV always on, or day care centers that let noise levels stay high -- may take longer to learn to talk.
"This might delay the onset of speech," Newman says. "Turning off the TV or radio, at least part of the time, would be a good place to start. Not all homes and daycare centers are equally noisy, but all caregivers should set aside quiet time or a quiet corner where infants can get the language experiences they need."
Newman's findings appear in the March issue of Developmental Psychology.