When baby needs watching and mom and dad get busy, the blue light of a glowing rectangle often beckons. Instead of playing another round of peek-a-boo while dinner burns, they may turn to a phone, iPad, or television to serve as a babysitter. Most babies now get screen time daily, according to recent data from the United Kingdom, with the average hovering around 41 minutes a day for 9-month-olds.
What does this screen time do to their tender, developing brains? Infants are thought to learn best by doing, particularly when it comes to language and social skills. They rely heavily on face-to-face interaction, shared attention, and live conversational feedback with an adult caregiver, decades of evidence suggests. Differences in social engagement abilities are also a major feature of autism spectrum disorder, and deficits in this arena have been associated with slowed language development.
Read more: “For Kids, Learning Is Moving”
To probe this question of how social interaction and screen time affect a baby’s brain, a trio of researchers from Northwestern University recently invited 49 pairs of parents and infants, aged 22 to 44 months, into the lab to play as they would at home, with a book or a puzzle or other toys. They then used electroencephalogram (EEG) headgear to compare the babies’ brain activity during natural play versus staring at a screen.
What the scientists found was that certain brain waves associated with attention, social engagement, and learning were more active when the baby was playing with a parent compared to when they were watching television, even together. The scientists found the same patterns in an independent sample of children diagnosed with autism. They published their results this week in Brain and Language.
I spoke with study author Elizabeth Norton, professor of communication science and disorders, about what social engagement looks like in a baby, what it’s like to get an EEG cap on a baby, and whether the results suggest that screen time inhibits language development.
The American Academy of Pediatrics recommends zero screen time for infants. Why is that?
Research takes so long to do, and what we know about screen time has evolved so quickly. For very young kids, there’s still not a lot of great information about how being in front of a screen affects their brain development.
And even for older kids, the American Academy of Pediatrics says some screen time is okay. It’s ideal when parents and caregivers can use that time together, almost in the way that they would when they’re reading a book, to use it as a jumping off point for conversations and back and forth interactions.
One of the factors that makes the AAP conservative or conscientious in their recommendations for young kids is that we know how important those back-and-forth reciprocal relations with caregivers and adults are for infants under two years old. I believe that being extra careful to make sure that families prioritize those interactions as much as is feasible is part of the reason for that recommendation.
And is all screen time created equal?
It’s really about having someone next to you and using screen time as a way to engage in what we call joint attention. An example is that a child might be playing with a Lego tower, building something, and the child and the caregiver’s attention are shared back and forth around that object. We know that’s so important for language development and social development and a lot of other things.
When screen time can be something that is shared that can be really productive. But of course, some families might need to have kiddos watch a screen for a few minutes while mom takes a shower or dad cooks dinner. In the real world, screen time for short periods can be a real necessity, but it’s ideal when it’s not just the child getting all of their language input from screens.
This study was presented as paradigm shifting because usually the social interaction and brain activity of babies are measured when they’re engaged in highly structured activities as opposed to more natural ones. Why had this approach not been tried before, and why is this shift so important?
When we’ve studied young kids’ language development and social development, we traditionally bring them into the lab and do things that really don’t align with their everyday experiences. We make them listen to streams of unfamiliar voices out of disembodied speakers, or we put single black-and-white pictures of faces up on a screen.
Even though with this study, we had parents and kids come into our lab, where it’s more feasible for us to put an EEG cap on the kid—and then also the parent for some additional analysis that we’re doing in future work—what we did is let them play like they normally do. We gave them books or puzzles and said, “Play like you were at home.” And we looked at their brains during those moments and compared it to what was happening in their brains when they were watching a video with or without the parent.
The real innovation that gets me excited is that we used to try to induce states of language learning or social processing in kids. And the real flip that we implemented here is to let those states unfold naturally. That is one of the things that was exciting to me, especially with the second study we did, where we included a group of kids who were diagnosed with autism.
So many studies show that kids who are diagnosed as autistic have differences in the way they process faces or listen to language, but it might be due to experimental conditions. The push to take our neuroscience tools from the really rigid and experimental to the real world is really exciting, potentially transformative for understanding a lot of things, including autism.
You found that social engagement in some of these activities went beyond eye contact. Is that correct?
We didn’t measure just eye contact. What we were measuring, to characterize social engagement, was that the parent and the infant were going back and forth and taking turns and engaging. We were watching the videos of how they engaged. It’s not just that they were looking at each other, which they might have been, but it’s deeper than that in terms of having a conversation, essentially.
Were there key elements of social interaction that you were looking for aside from eye contact?
We adopted a framework that’s been used in previous studies to look at how a caregiver is responsive to their child’s behavior, which we know is really important for child development. We were looking for the stretches of the interaction where there was that back and forth of shared attention related to an object, a movie, a puzzle or a book.
Do your findings suggest that screen time may inhibit language development?
I would not go so far to say that screen time inhibits language development. This was a one-time study and so we want to be careful about talking about longitudinal consequences.
One of the things that this tells us is that there are signatures in the brain that we can identify from previous studies that indicate that the child is paying attention, they might be ready to learn, and we see those a lot more in the moments when they’re just engaging with their caregiver and not as much when they’re just engaging with a screen. We can’t necessarily say that screens are detrimental, but we do see patterns that are consistent with what we might want to see for learning when the child is going back and forth with their caregiver.
You found that toddlers with slower language development and autism diagnoses showed similar brain patterns to children with typical development in the moments when they were engaged with the caregiver. Does this mean they are generally more engaged than we thought?
It tells us that there are more universals in language development and language learning than we might have thought. And some of the differences that we’ve seen in previous studies, for example—which have found that groups of children who have been diagnosed with autism look at faces differently—might be related to the fact that these studies were not very natural. It’s not very often in our daily lives that we see a black and white representation of a face and think about how to engage with it.
You plan to look next at whether parents and toddlers’ brains are in synchrony when they’re interacting. What will this tell you?
The idea of looking at brain-to-brain synchrony is quite new. A few studies have done it, but very few have done it in parents and kids. We’re hoping that it’ll offer another window into what it means to be interacting with another person and offer a new type of insight that we haven’t had before.
There have been a few studies in classrooms where a bunch of students were wearing an EEG cap, as was their teacher. Some students were more in sync with their instructor than others. It’s a pretty new area because collecting EEG on multiple people at a time is even more tricky than collecting EEG on a single child, much less a toddler.
How tough was it to get an EEG cap on the babies?
One of the trickiest things that research has been able to do is to try to look at the brains of toddlers because they don’t want to stay still in MRI. It’s hard to get them to do a task like looking at faces even in EEG.
That’s why I’m so excited about this idea of bringing the naturalistic play context into our brain imaging work rather than trying to fit the square peg of toddlers into the round hole of neuroimaging. And actually, what we do, even if we don’t want to look at both the parent and the toddler’s brain together, we put an EEG cap on the parent. When the toddler sees, “Oh, we all wear a funny looking hat when we’re here,” it helps us increase the rate at which we can get toddlers to do a task, even if it’s not a fun and engaging task like the social EEG paradigm. 
Enjoying Nautilus? Subscribe to our free newsletter.
Lead Image: Northwestern University