In the 2020 Netflix documentary series “Babies,” a University of California, Merced, psychologist explained a startling discovery he made in 2008 as a graduate student: early walkers not only have more advanced gross motor skills but also larger vocabularies than babies who are only crawling.
The psychologist, Eric Walle, still doesn’t know exactly why. Maybe the coordination of the left and right sides of the body helps the neural pathways on the left side of the brain, where language activity is centered. A more likely explanation, Walle thinks, is that when babies start walking, they can move toward and pick up all kinds of objects that interest them and show them to adults while interactions with the world are more limited for crawlers.
For years, no one believed that learning to walk (a gross motor skill) and learning language (a cerebral skill) could be so intertwined but in 2014, Walle eventually persuaded the academic community that his research should be published.
Parents of late walkers might have fretted. Would their babies be doomed to a life of few words? Walle suspects that the crawlers catch up with the early walkers, both physically and verbally, but now he has a new study for anxious parents. There are ways to talk to your little crawler that can close the language gap with babies who are already walking, he says.
“Walking somehow boosts language learning in infants but it’s by no means the only way that children learn language,” said Walle.
In a follow-up study of 13-month olds, Walle found that crawling babies had larger vocabularies when their parents directed them to play with a toy or an object.
“When parents are encouraging their child to interact with objects more frequently, their crawling infants have a vocabulary that looks more like that of walking infants,” said Walle in an interview about his latest research findings, which have not yet been published in a peer-reviewed journal.
“If you see your baby interacting with an object, you can say, ‘Oh yeah, push it, push it here. Push it. Push it there,’” said Walle, offering an example.
Ordering your child to do something might not seem like enlightened parenting but Walle argues that certain kinds of directives are helpful in language development. Walle said the key is to begin by taking the lead from your baby and notice first what captures his or her attention.
“If you’re looking at your phone, you might miss those really important opportunities,” said Walle. “You couldn’t create these moments even if you wanted to, for the child creates it for you. I would encourage parents to be attuned to those teachable moments in everyday life. The importance of these little moments adds up.”
Half the babies in this study were already walking and this particular kind of parent talk didn’t boost vocabulary for them. Only the crawlers whose caregivers talked like this had larger vocabularies, as measured by a survey of 396 words that parents filled out. (Parents checked words that they believed their baby understood but not necessarily spoke.) Walle believes that walking infants might not benefit from this kind of verbal direction because they’re already able to move toward objects that interest them and play with them on their own.
Walle’s conclusions about talking to crawlers are based on two small studies, each involving fewer than 75 babies, that he conducted in families’ homes and in his laboratory. But they’re part of a broader body of early childhood research making the case that it’s not how much you talk to your child that matters, but the quality of the conversation and the nuances of the back-and-forth interaction that can be more important in brain development.
Research that analyzes the verbal interactions between parents and children has exploded in the past decade thanks to advances in wearable audio recorders and natural language processing technology that have made it more practical to “listen” to hours of speech inside homes. In Walle’s studies, he compared infant noises and caregivers’ utterances with a parent survey of words the child understands.
Making sense of this babble is difficult. Though Walle’s original research found that walkers had larger vocabularies, he didn’t find that to be the case in this new follow-up research. Thirteen-month-old crawlers knew as many words as 13-month-old walkers. Maybe the walkers hadn’t been walking long enough to develop a bigger vocabulary. But perhaps Walle’s theory also needs some refining.
All of this research is young and based on small studies. It’s intellectually fascinating to follow researchers trying to piece together how babies’ brains develop but parents shouldn’t rely on it for parenting advice. “As a parent of a toddler, I did not even think about it,” said Walle. “What I would say to parents is just be attentive to your baby.”
Walle’s advice to get off your cell phone some of the time seems pretty sound.
This story about language development was written by Jill Barshay and produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education. Sign up for the Hechinger newsletter.