The study, conducted by Mary Fagan, an assistant professor at the University of Missouri School of Health Professions, involved 43 babies. Twenty-seven could hear, and 16 had "profound" hearing loss and received a cochlear implant. Before the implant, those 16 children rarely made repetitive sounds, like "da-da." But after receiving the implant, they not only made those repetitive sounds more frequently, they sounded out more of them at once ("da-da-da-da," for example). In fact, before long they were babbling as much as babies who were born with good hearing.
The study was published in the Journal of Experimental Child Psychology.
Fagan was most interested in seeing how cochlear implants—and the subsequent ability to hear—impacted a child's speech development. (Answer: A lot.) But her findings are useful for parents of hearing infants as well, because they show that our babies aren't just passively listening to us, they're also actively trying to participate in their own speech development.
"The research tells us that infants are motivated by hearing the sounds they produce, so these sounds are functional in some way," Fagan said. "Research conducted by others supports the idea that babies form mental representations of their own babbles, such as these strings of syllables, which may be the reason that infants tend to use the sounds that they have babbled in their first words rather than the sounds that are most common in the speech that adults use with them."
That said, it's still important for you, your partner and your child's caregivers to keep up the chatfests. "This research doesn't diminish the importance of the speech that babies hear from others—we know they need to learn from others—but it raises our awareness that infants are not just passive recipients of what others say to them," Fagan points out. "They are actively engaged in their own developmental process."
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