Ask A Scientist: How Does Where Babies Look Affect What They Learn to Say?
It's incredibly difficult to learn a second language as an adult, but it's much easier for young children. Not to mention that babies learn an entire first language without a single textbook or Rosetta Stone tutorial. Scientists are still working out how exactly babies' brains allow them to accomplish this incredible feat.
Rechele Brooks, a research assistant professor at the University of Washington in Seattle, studies young children's social skills. She and her colleagues, Barbara T. Conboy, Andrew N. Meltzoff and Patricia K. Kuhl, recently completed a study that looked at how a specific baby behavior, called gaze shifting, allows infants to learn language. Specifically, they wanted to know whether a higher frequency of this one behavior helped children learn a language other than the one their parents spoke at home. It did.
We spoke with Brooks about her latest research for our latest edition to our "Ask A Scientist" series.
The conversation below has been edited for length and clarity.
What does gaze shifting look like in young children, and why is it important?
You've probably experienced it many times yourself with adults and with children. It emerges when people are really young, around nine months. We've been looking at how well children make eye contact with a person while they're playing with a toy; how they go from looking at the person's eyes and face down to the toy. It goes back-and-forth.
If a mom and a child are playing with a toy duck, the baby might have the duck in her hands and be playing with it but then glance up at the mom. For our study, either the up to the face or back to the toy counted [as a gaze shift].
This alternating back-and-forth is so fragile when they're really young. They don't do it very often. They are just emerging this ability. When they're younger [newborns], they're really good at making eye contact. Then later when they start picking up toys, they're really good at playing with toys. But coordinating back-and-forth is really fascinating to watch [emerge]. In some ways it's like they're initiating a conversation with their parents just with their eyes.
We've shown in our lab and in other labs as well that how well infants are able to shift their gaze coordinates with their language development and predicts how large their vocabulary will be when they're older.
Our project is one of the earliest reports of how gaze shifting can help language development. A lot of the other research has shown that when children are past their first birthday [the regularity of gaze shifting] can predict how well they're going to learn vocabulary.
How are you able to measure that 9-month-old babies learned language if they don't speak?
The babies [from English-speaking homes] came into the lab and played with adults who were speaking Spanish to them. During those "conversations," that were rather one-sided as far as language goes, the adults spoke Spanish and the babies played and used their eyes to do their part of the conversation.
We were able to find out how often were babies making eye contact back-and-forth between a toy and a person, so we measured how often they did that during their playtime. Then after they were done with their Spanish tutoring session we had the babies come back and [listen to] speech sounds. [Speech sounds] are the basic building blocks of words, like "ba," "da," and "ta". All of those little sounds are phonemes.
Young babies come into the world knowing all these different speech sounds—they can tell them all apart. What happens in a regular development is that, as kids learn their home language, they focus in on the sounds that they're hearing at home.
[In the study though,] we had babies [who primarily heard English] now hearing Spanish. Would they learn the Spanish that they're hearing at the University of Washington lab?
The brain has a pattern of recognition when they notice, "Oh, you said something new?" Babies in the study were better able to recognize the Spanish [speech] sounds. And the babies who have been shifting their gaze more often during play with the actual people were better able to recognize the different [Spanish] speech sounds when we tested their brain reaction. In other words, they had learned the new sounds of the new language, and we were able to recognize it by reading their brain waves during the study.
It was pretty exciting to see how well they had learned Spanish and how strongly that correlated with how much they had been alternating their eye gaze or gaze shifting during the playtime.
Were these babies also compared to babies that weren't being taught Spanish to ensure it wasn't a fluke that they recognized Spanish sounds?
No. But we did ... [answer that question in] our Mandarin studies. We were able to show that babies who aren't exposed to Mandarin don't learn Mandarin [speech sounds].
That study also showed that if the babies were exposed to Mandarin by a video recording of one of our Mandarin tutors, or an audio recording of our Mandarin tutors, those babies also didn't learn Mandarin Chinese. [They only learned it if they heard it directly from a person.]
We did test if the babies could tell the difference between the Spanish sounds [at the beginning of the study. They coudn't.] It was only after they had been interacting with the person speaking Spanish that they could notice the Spanish sounds.
Do you have any sense of what characteristics of a given baby might make them more likely to do more gaze shifting?
We didn't test for that in this study. In general, people are starting to look at those questions, but that's actually a big question for our field of developmental psychology: Why [is a baby] going to be more likely to socially engage with parents?
Is there something you think preschool teachers can do knowing this?
Future directions could include: How well do kids learn in small groups? How well are you interacting with and talking about real objects? How much does that ground language learning and give children an opportunity to follow what you're looking at?
I think it's a really fascinating question that we're just getting a better handle on.
Are some babies born more likely to do a lot of gaze shifting than other babies? Or is gaze shifting something that increases when babies are actively engaged with adults?
It's an interesting question. No one's ever tracked a newborn up to age 9 months. They've looked at some kids starting at 2 months, but I haven't seen any strong patterns jumping out at me. Our learning at the institute has always been that if you're engaging and interacting with your children, you're providing them with opportunities for learning. There's research to back that up—that the parents who are engaging their children and tuning in to what their child is doing give their children more opportunities to learn and grow.
If your child is holding onto a ball and you talk about, "Oh, the ball is polka-dotted," then the child has an opportunity to alternate her gaze between you [and the ball]. But if your child is holding a ball and all of a sudden you want them to look at a book even if the child's not done with the ball, making that shift is hard for kids. When parents tune into what their child is already doing, that helps kids tune into language. It's very much a two-way street. That bidirectional nature of playing with your child and interacting with your child for a moment ... well, all those moments add up, and children start learning all about their social world.
How many children were part of this study?
This study had 17 children who finished everything. I feel like that's somewhat small of a sample, but when you consider it in terms of all of our other very parallel [study] designs, it makes me more comfortable to say that the pattern is important even though we only [looked at] 17 children.
A lot of brain-behavior studies used small sample sizes. It's such a labor-intensive project to recruit and have families come in for 12 different visits and then come before and after for measures of language learning or brain development.
I'm wondering if we'll eventually be able to have a measure to know if eye gaze helps us to know when they're ready to learn. And, how well can we use this early behavior to figure out other aspects of social development? And, would we be able to use some of this early processing of eye gaze in a larger group of kids to see how well it works? Does it help with [learning] the first language?
There's a whole world of questions. I feel like one study opens up five more questions, then you know you've done a good study because you think broadly about what you want to do next. I'm excited to see how it all goes.
Video clip by the Institute for Learning & Brain Sciences shows a baby gaze shifting during play.