Written by Catharine Paddock PhD
A new study that offers insights into early language development suggests babies prefer listening to other babies rather than adults as they get ready to produce their own speech sounds.
The study, led by McGill University in Canada and published in the journal Developmental Science, observed the reactions of infants aged from 4-6 months who were not yet attempting speech, as they listened to baby-like and adult-like sounds produced by a voice synthesizer.
They found when the vowel sounds the babies listened to sounded more baby-like (for instance, higher pitch), the infants paid attention longer than when the sounds had more adult-like vocal properties.
Previous studies have shown that children at this age are more attracted to vocal sounds with a higher voice pitch, the authors note in their paper.
The team says the finding is important because being attracted to infant speech sounds may be a key step in babies being able to find their own voice - it may help to kick-start the process of learning how to talk.
They say the discovery increases our understanding of the complex link between speech perception and speech production in young infants.
It may also lead to new ways to help hearing-impaired children who may be struggling to develop language skills, they note.
Baby-like sounds held infants' attention nearly 42% longer
For the study, the team used a voice synthesizer to create a set of vowel sounds that mimicked either the voice of a baby or the voice of a woman.
They then ran a series of experiments where they played the vowel sounds one at a time to the babies as they sat on their mother's lap and listened. They measured the length of time each vowel sound held the infants' attention.
The results showed that, on average, baby-like sounds held the infants' attention nearly 42% longer than the adult-like sounds.
The researchers note that this finding is unlikely to be a result of the babies having a particular preference for a familiar sound because they were not yet producing those sounds themselves - they were not yet part of their everyday experience.
Some of the infants showed their interest in other ways. For example, when they listened to the adult sounds, their faces remained fairly passive and neutral. In contrast, when they heard the baby-like sounds, they became more animated, moved their mouths and smiled.
The following video shows how one of the infants - baby Camille, who is not yet babbling herself - reacts to the various sounds. Every time she looks away, the sound is replaced by another. Her reactions show which sounds she seems to like the most.
Babies need to 'find their own voice'
The researchers say maybe the babies recognized that the baby-like sounds were more like sounds they could make themselves - despite not having heard them before.
The findings may also explain the instinct some people have when they automatically speak to infants in baby-like, high-pitched tones, says senior author Linda Polka, a professor in McGill's School of Communication Disorders, who adds:
"As adults, we use language to communicate. But when a young infant starts to make speech sounds, it often has more to do with exploring than with communicating."
Prof. Polka says babies often try speaking when they are on their own, without eye contact or interaction with others. She explains:
"That's because to learn how to speak babies need to spend lots of time moving their mouths and vocal cords to understand the kind of sounds they can make themselves. They need, quite literally, to 'find their own voice.'"
Funds for the study came from the Natural Sciences Engineering and Research Council.
Meanwhile, parents and schools looking for ways to encourage children to eat more healthily may be interested in a study carried out among kindergarten through sixth-grade students at an inner-city school in Cincinnati, OH. There, researchers discovered that children found healthy food more appealing when linked to smiley faces and other small incentives. The low-cost intervention led to a 62% rise in vegetable purchases and a 20% rise in fruit purchases.