In Review
SCREEN TIME: Two-year-old Jackson Coles, of Webster, N.Y., watches a special monitor designed to track eye movements as his
mother, Christy, identifies objects on the screen during a research study to explore how children use verbal hesitations as
clues to understanding new words. (Photo: Adam Fenster)There鈥檚 good news for parents who are worried that they鈥檙e setting a bad example for their children when they say 鈥渦m鈥� and 鈥渦h鈥� when they鈥檙e searching for the right word.
A new University study shows that toddlers use their parents鈥� stumbles and hesitations to help them learn language more efficiently.
Say you鈥檙e walking through the zoo with your two-year-old, hoping to expand your child鈥檚 vocabulary of wild animals. You point to a rhinoceros and say, 鈥淟ook at the, uh, uh, rhinoceros.鈥�
As you鈥檙e fumbling for the correct word, you鈥檙e also sending a signal that you鈥檙e about to teach your child something new. In other words, your youngster takes your verbal hesitations鈥攜our disfluencies, as they鈥檙e known to cognitive scientists鈥攁s a sign to pay close attention, according to the researchers.
Richard Aslin, the William R. Kenan Professor of Brain and Cognitive Sciences and one of the study鈥檚 authors, says young kids have a lot of information to process while they listen to adults speak, including many words that they have never heard before. Deciphering what a word means after it鈥檚 been spoken is a more difficult task for a young child鈥檚 brain, and a child is apt to miss what comes after the new word.
鈥淭he more predictions a listener can make about what is being communicated, the more efficiently the listener can understand it,鈥� says Aslin.
The study, which was conducted by Celeste Kidd, a graduate student at the University, Katherine White, a former postdoctoral fellow at Rochester who is now at the University of Waterloo, and Aslin, was published online in the journal Developmental Science.
The researchers studied three groups of children between the ages of 18 and 30 months. Each child sat on his or her parent鈥檚 lap in front of a monitor with an eye-tracking device. Two images appeared on the screen: one image of a familiar item (like a ball or a book) and one made-up image with a made-up name (like a 鈥渄ax鈥� or a 鈥済orp鈥�). A recorded voice talked about the objects with simple sentences. When the voice stumbled and said 鈥淟ook at the, uh . . . 鈥� the child instinctively looked at the made-up image much more often鈥攁lmost 70 percent of the time鈥攖han the familiar image.
鈥淲e鈥檙e not advocating that parents add disfluencies to their speech, but I think it鈥檚 nice for them to know that using these verbal pauses are OK鈥攖he 鈥渦h鈥檚鈥� and 鈥渦m鈥檚鈥� are informative,鈥� says Kidd, the study鈥檚 lead author.
In the study, the effect was only significant in children older than two years. The younger children, the researchers reasoned, had not yet learned the fact that disfluencies tend to precede novel or unknown words.
When kids are between the ages of two and three, they usually are at a developmental stage where they can construct rudimentary sentences consisting of about two to four words. And they typically have a vocabulary of a few hundred words.
The study builds on earlier research by Jennifer Arnold, a scientist at the University of North Carolina and a former postdoctoral fellow at Rochester, which found that adults also can use 鈥渦m鈥檚鈥� and 鈥渦h鈥檚鈥� to their advantage in understanding language. Additionally, work by Anne Fernald at Stanford University has shown that it鈥檚 not the quality but the quantity of speech that a child is exposed to that鈥檚 most important for learning.
Alan Blank writes about the sciences for University Communications.